hey Lorena,
as Stacey already said, you could use Skype if he has internet access...another option is that he could use a CiCi card...or an equivalent? In Ontario we have CiCi cards which are calling cards, and they don't have any access fees, so $20 is $20 of talk time (which actually goes a long way). He'd call a 1-800-#, and that might show up, but it would be free, and then he'd be able to call your cell, it just means that you would have to wait for him to call you.
Good Luck finding a solution!