its better money system where the money well be paper and you can create shop with this plugin and when someone kill you he well take your money so if u r intrested ill send you more details
Emeralds are coming in 0.9.0, so you can use that, and use a sign shop to do exchanges, paying with emeralds.
Really, you'd be able to use anything, and if you don't use emeralds, then this is already possible. I just suggested emeralds because they are the "Minecraft currency" that Mojang has created.