Everyone is suggesting treasure maps... but the rewards from the treasure maps is way way too good for a low rate server. How about changing treasure map entirely?
1. Map treasure maps be able to drop from all mobs, always. All mobs will drop the same treasure map (no more low, mid, high, unknown)
-.1% change to drop from normal mobs
-1% change to drop from db/cyc/fatal/balroc/succubus
-10% chance to drop from mini-bosses in dungeons
2. When opened, the mobs will be randomly chosen (can any the mobs from low/mid/high)
3. the Drops need to be change 100%. Make the treasure maps drop ONLY:
-critt (1mill piles)
-1 sard per map
-1 leaf per map
-jobbing items (diamonds, whitbirch, etc)
-Resurrection Elixir
-Reparation Elixir
-random G1 items (NOT rings or neck)
-RE (random value between 1-50)
This way people have a way to earn RE through the game but not in a way that it will take too much money from the server. Players can enjoy something that's always fun and different to do. Players have an alternate way to get sards other than quests.