Instead of doing that - the admins/mods can activate 'plot buy & plot lock' - it's an CSBM/envul add-on. Players would be able to 'buy plots' and have the option to 'lock' them - which would kick out/teleport anybody who is not on your 'CSBM/envul friend list' (you can add them by doing /friend add (name). The only problem which plots is that people can abuse it and buy up public areas - towns/stores and lock them down.
Therefore if they do enable plot buys/locks, then they should charge a maintenance fee (should be decided). Doing plot locks would also prevent hackers from entering locked places - it should kick them out because they aren't friends with the plot owner.
Also, you would/could have to make a 'zgate' for the shop.
There is another mod where players can sell 'game server items,' but those are set in quality & etc, it'd basically be another 'server' shop, but the player can change the price.
Or what you could always do is....ask them to make a deposit? - like say if they're paying with zcoins - a deposit of ~500, then you could either have them pay the difference, or something like that.