Back in 2007 when I was new, it was the standard practice that private sims sold parcels the same way as mainland. So, you pay an initial purchase price, monthly tier payment, and then sell the parcel to someone else when you didn't want it anymore. I paid 79,000 L$ for a parcel on a guy's private estate continent (I forget what the monthly tier payment was). The original owner sold all his sims after a few months.
The new owner set up a rent box to accept the monthly payments. The first time I paid my monthly payment, I paid it before logging out for the night. Because I logged out after paying, I did not notice that the rent box gave me back the monthly payment because it was not configured properly. The next day, my parcel had been reclaimed and sold to someone else. When I asked the owner about it, he acknowledged that his rent box wasn't working, but refused to either give the parcel back or return the 79,000 L$ I had paid for it.
So that was my first Second Life economics lesson.