"Within six months there will be stores everywhere loaning them money against their next government check. Or next years'."
Sounds like a pretty risky business to be in to me. Would you be interested in opening up a busines like that? If not, why do you think other people would?
There are already thousands of "stores" out there loaning money to the "poor" on the basis of their future EITC checks and other "benefits" - Social Security, welfare, etc.. They must be making a profit, since they are still out there. The Fair Tax just enlarges their clientele.