I hope you realize magic in general has a hefty price tag. Though I do agree most mentalism props cost 10 to the nth degree more then most decks of cards. Especially the props from Outlaw effects. *drools over the wallets*
Anyway I am going to completely contradict myself by saying, mentalism is the least expensive form of magic because you do not even need any props to perform the feats.
thats a confusing post, but i follow you!