Only read the minds of those people who show a more {expensive} read than the rest in the area!!! The reast are just a waste of your experience points!!!
Friendship is like peeing on yourself: everyone can see it, but only you get the warm feeling that it brings.
While that's generally true, there are a few low cost mind-reads worth doing. Linda in the mill for example only requires 40 EXP to have here mind read. When you find the purse you can keep it for 100g or return it for 100 EXP earning a net gain of 60 EXP. Not much but useful when your first starting.