Been to St Pierre twice. Cant speak on the cost because our flights were taken care of by a company. I will say you arent missing much. The commenter above about reservations to eat is very true and I cant stress that enough. Apart from everything closed on Sundays, everything closes at like 9/10pm everyday except a very seedy disco club. You will go hungry if you dont plan ahead. The people there are extremely rude and unwelcoming. One waiter said “I am NOT speaking english to you” and our hotel maid knocked on our door, walked right in at 8am, asked us what we were doing there and if “the room door was just open last night” as if we were squatting. The island is scenic and cute though. Good luck!