Well it could say "Door lock must pay (amont of money) type /paydoor (amount of money) to get in." If you try to open it.
pbrassat17 honestly, I didn't read yours until after you asked. I remember someone else making a suggestion a while ago about an in Spawn trade building, but it was denied. Not saying you have a bad idea, just that I didn't see it until afterward
Only problem i can see...is one user paying for it..setting a home, then tping others past the door. Also there are manys ways to get around doors with perms/without perms.
2 ideas that could work for this, 1, make it so for example after that time it autoruns a command like rg removemember (Townname) (username), another is have it so there is a ingame application for something like this and make it so that nobody can do /tp, /sethome, /tpaccept, and so on in here.