Bukkit

Newspaper is the plugin to use to get information around your server as quickly as possible.

SimpleMoney Reloaded

Allow players to rent rooms for a certain amount of time.

AllBanks

A permission, economy, auto-ranking plugin based on requirement(s). Ranker tracks wealth, pvp, pve, and time to determine Rank.

Fills the player's XP into a bottle

ITEMEX - Players can exchange all Items with other players (FREE MARKET)

A user-friendly economy plugin that adds player made shops.

SuperPotions

[ECON/SEC] AEco v1.0 - Simple Economic, Shops and Locks [1337]

Create villager that sell up to 8 items using vault

Allows normal users to disguise themselves as mobs for CommandPoints!

Skyowallet is a lightweight economy which supports Vault and MySQL.

Makes trade offers of villagers use fair prices, geared toward removing exploitability while leaving trading usable.

Spawning player heads

MobCash gives players money when they kill a mob

Full featured protection cuboid plugin with factions.

rbuy

Buy and rent WorldGuard regions. Provides taxes, size-based prices, an inheritance-system and much more

Adds a line of text on screen that shows how full your wallet is.