I have noticed on the server time to time people selling access to farms for a period of time or a one time entry if you leave you must pay to get in. My question is does this mean you can give a person only access to open say a gate to get into a farm then they may farm whats inside but can not affect the town otherwise? Any info on this would be appreciated Thanks
No, once you add them to the town they can break or place any block inside the town. They also need to be added to the town to be able to farm anything, as breaking pumpkins/melons/wheat is still considered breaking a block. Which they can't do if they don't have town permissions. You just have to add them for the time they are farming and then make sure you take them off when their time is up.