Notice that for each character you assign who's role is whose, they each get different abilities.
Also, if you're looking for a way to spend your money, check out the Gamble section of the shop, as well as the armory to improve your current items. The accessory's section can get you rare items like EXP RING, or especially the GREED RING.
a tip for avoiding fights by dodging the monsters. when you enter a room on the right, immediately place your mouse on the left, then you can click around any monsters that are super near by.