So, the associated gp cost is similar to that of a magic location, meaning that the DM subtracts it from the party wealth, correct? Why would the other players agree to lose money so that you could get a feat?

An interesting, if overpowered, concept. Shouldn't it be a permanent +2 bonus on will saves, so that you can train to improve your willpower even more and to avoid using it to qualify for prestige classes?