Having full LUCK set can be very helpful after lvl 80, especially for mele classes with more defense.
I personally use Aramid Martial set of Luck and Bluestin Orbs with 20/30% alz drop for each part. The type of armor doesnet matter as long as u can wear it and give at least 20% alz drop amount.
Using that set in Undead Ground or Fort Ruina can provide you with good amount of alz drop.
For example in Undead Ground if i dont use Luck set i get around 800/900 alz per mob. Using Luck set gives me around 3900/4000 alz per mob. Grinding in Undead ground can be very profitable, since the mobs drop Osmium Armors and world entry items.
Also u will drop some items while u farm:

Personal Benefit : FR (Fort Ruina)
- Alz & Alz Boms
- Chaos Lamps / Map Parts / Ruina Stations
- Cores (Upgrade Core Medium & Force Core Medium)
- Extract Potions (DEX / INT / STR)
- Discs / Shapes Lv 2
- Titanium Stuff - Material Core Titanium
- Other Materials / Circuit Jewel Lv 2
- Amulet of Guard +5 / +6
- 1 Slot Titanium Stuff

Personal Benefit : UG (Undead Groud)
- Alz & Alz Boms
- Chaos Lamps / Frozen Tower B1F / Ruina Stations
- Cores (Upgrade Core High & Force Core High)
- Extract Potions (DEX / INT / STR)
- Discs / Shapes Lv 3
- Osmium Stuff (Gear) & Titanium Stuff (Weapons) - Material Core Osmium & Titanium
- Other Materials / Circuit Jewel Lv 3
- Various Amulets / Rings
- 1 Slot Osmium Stuff & 1 Slot Titanium Stuff

*NoTe* - For ALL the Stuff that you get from Farming you get Alz !
*NoTe* - The Discs / Shapes / Material Core / Circuit Jewel / AoG / Slotted Titanium - You sell them at AH, Osmium u sell to merchant

You need:
I. 1x Aramid / ShadowSteel Set of Luck (Maximum Alz Drop Rate (30%) / Item|*NoTe* - Gloves only have 2 Slot Drop Increase (+3 - 200%)
II. 1x Amulet of Seven Coins/ 2x Ring of Seven Coins (|40% Alz Drop - Amulet / 20% Alz Drop - Ring)
III. 2x Bracelet of Seven Coins/ 2x EarRing of Seven Coins (20% Alz Drop - Bracelet / 20% Alz Drop EarRing)

With a set like theis one you will have :
> 310% Alz Drop Amount Increase (You will see that from every mob you will get 3 - 3.5K Alz in FR & 3.5 - 4K Alz in UG)
> 200% 2 Slot Item Drop Chance Increase

The Cost involving an Alz Set (Aramid / ShadowSteel of Luck) are Very Low :
- Helm - ~ 200k
- Suit - ~ 400k
- Gloves - ~ 200k
- Boots - ~ 200k
- Amulet - ~ 200k
- Ring - ~ 400k
- Bracelet - ~ 500K
- EarRing - ~ 200K
Total : Around 3 - 4KK

My advice is to START Farming right now ... Buy a Set of Luck and you will see your Alz growing and growing.
For every Hour in FR (At MechZards / Auto Cannon Ex) you will get 1.000.000 Alz with a proper Alz Set.
For every Hour in UG (At Lihorn Zombie) you will get 2.000.000 Alz or more with a proper Alz Set.
Good Luck !

There are 3 dungeons at lower lvl that give good profit every time. As fast you can make the dungeon as fast alz you will get.

1. Lake in Dusk - Entry item - Map Part lvl65

The dungeon at low lvl is good for grinding and at high lvl is good for drop. The items you get from LiD are :

The Final Boss have chance of droping Unique Armour parts and weapons, that costs millions.

2. Ruina Station - Entry item - Muster card lvl75

At low lvl good for grinding and at high lvl good for drop. The spot you got to aim for in both cases, grind or drop, is the Buffalo Room near the end of the dungeon. The room is full of MechaBuffalos ( more than 30 at same time ) and they respawn verry fast. If you manage to kill em fast enought they drop :

The last boss usualy drop Crap

3> Tower of the Dead. - Entry item - Epaulet of the Dead lvl85

The dungeon doesent give much exp as LiD or RS, but give much more profit for finishing it. Usualy when you go out you have profit from 2-3 mil.
Items that can be droped :

The last boss have chance of Unique drop, mostly Osmium ( 200mil+ )

So, how to make alz? If u have titanium parts with 1 empty slot u can try your luck. You need:
1. titanium with 1 slot +0 (its important that it should be +0)
2. 2 force core (medium or high)
3. 50.000 alz

You go to core alchemist and press "force core upgrade".

After upgrade you can get in slot randomly lvl 1 or lvl 2 upgrade or fail. If you fail, you loose your cores.

So, what now? Now u can sell titanium with upgrade in slot. Look at this list and you will see if your upgade worth something:

Suits:
with +50 hp or +20 def rate have middle price
with +2% max crit rate - high price around 20-30 mil

Helmets:
with defence +2 and defence rate +20 has middle price
with +5% crit rate - high price

Boots:
with hp+50, defence +2 and defence rate+20 has middle price
with hp auto heal+2 - high price

Gloves:
with 2% hp steal, defence+2 or defence rate +20 has middle price
with 2% max crit rate - high price

Think for the future...
That is a quest that you will get at lvl 98. Dont finish it!!! Leave it for later and it will give you verry good profit after lvl 120-140!
The dungeon is short one, full with hard mobs and bosses that drop osmium armors with slot. There are 6 bosses before the Patren boss ( which you dont have to kill!!! or you will loose the dungeon )
After killing the 6 bosses you simply relog and start it again. After lvl 140 you can make the dungeon in 5 min. and in 1 hour you can fulfill youre inventory 2-3 times with sloted osmiums. Selling em to NPC can give you verry good and fast profit.
The location of the dungeon is :

Well...crafting can be tricky!!! For making good profit from crafting you got to give a lot of money to achieve high lvl crafting.Most of the ppl stop around bluestin or titanim ,cause it gets too expensive to craft and they need the alz for armors,skills and upgrades than.But after passing Titanium/Phery the crafting starts to give good profit. And reaching lvl as osmium or above will make win you millions for sure! Its realy up to you if you wanna become crafter and invest money in that!

Thats another thing that is popular in every MMO. I think that there are no needed further explanations for what you must do here. Finding some cheap items and reselling em is all familiar action to us! We cant say whats good for resell atm and what is not, cause the economy of the game changes every day. So it will all comes in time. |You play, you see how prices goes, you find and you resell if you think its wise

DT cards are 2 types. SOLO and PARTY.

Solo cards we leave behind....i suggest you to not enter that cards at all, unles youre not 140+, even if the card is for lvl 50

So we aim at DT party cards and especially lvl70 cards.
WHY?!
Becasue at the end of the party dungeon there are 3 bosses.
If the card is for lvl70 they drop:
Upgrade core medium and high
Force core medium and high
sloted titanium armors ( perfect for 2nd lvl upgrade or selling in AH )
2 sloted titanium armors ( can be sold for good amount of alz, cause theyre needed for crafting )

At low lvl you might need all the time the dungeon offer you ( 30 min ) to kill the bosses and to finish it. But at higher lvl 100+ you can make the dungeon 2 times in a row.
HOW COME?!
Well the mobs as the bosses at that dungeon respawn at every 10 min. If you manage to make it to the last room and kill the bosses and you have more than 10 min left after you kill em, they will respawn again and you will kill em again, getting 3 more drops. ( not bad at all )
But for making it happen, yo got to leave some mobs from the last room alive, cause if you kill all mobs and bosses the dungeon will end. So, before u kill the bosses in the last room, make few steps thrue the door of the boss room and try to get the attention of the first 1-2 mobs in the room, without disturbing the bosses. Pull the mobs of of the room in the room before, and when they come far away from the door, dash to the boss room and leave the mobs behind. So after you kill the bosses and the mobs in the room, there will still be alive mobs and the dungeon will continue, so you can kill the bosses again in 10 min.
The only bad thing is that you got to wait 10 min in there dancing filling youre SP or chating with friends, till they respawn...
Added: or praying about good drop:D