I fail to see why you can only use them once after paying 27,500 currants. You have to consider the economics of the game and realize how much 27,500 is. It's about equal to one of those houses in Alakol which is yours for as long as the houses are in the game. I bought one, figuring it was yours forever. When I found out it was not, I was like might as well sell it and get testers. Others will be less forgiving and may rage quit. They should change in one or more of the following ways:
1: Sell Testers only.
2: Warn users they are used only once before buying.
3: Make it economically on par with other items in the game because right now it's not.
Cheaper parties would encourage more social interaction which is good for the game overall :)