Is there any stores or restaurants were I can not use American Express Travellers Cheques?

I am going into the states for a while in April, and I am wondering if there are any stores or restaurants or any place else that will not except American Express Travellers Cheques. Also, is there are charge to use them? I asked two different banks, both the same branch, just different locations, and one said there will be a fee when I use them, and not all locations will use them, and the other said there is no fee and I can use the any were. So I need your help, thanks.