I was on an smp server and they had a credit system in place each removed or placed block was worth .5 credits and you needed 10000 credits to buy a zone witch was something like 100x100 and sky to bedrock and no one else could do anything else in it. You could also buy and sell things that you gathered in a shop of sorts, could also trade them. I wish I knew what the Plugin was, I would like to use it.
sounds like an assortment of plugins, not just one. and a lot of configuration to get it to do what they wanted.
Residence, towny, factions or regios As for the money, you'd need an economy plugin such as iConomy (the best one), BoseConomy.