You can save up before mind read to decide yourself whether the content is worth wasting the exp or not. There are a lot high cost mind read which actually provide items which totally useless. And when you reach later game, even mind read some stupid merchant for discount also will cost you few k exp, so it will be hard by just judging through the amount of exp needed for mind read.
Wow lvl38, I bet that guy had extremely high investment on the skill wisdom. Else I dont think is possible.
