My husband has been my sons father since he was 3, and now my son is 7, and wants to have the same last name as the rest of the family. About how much does the process cost for him to adopt my son?

Assuming the bio father will sign off on it, about 5000 dollars.
But if bio father will not sign off for it, first it may not even be allowed, but it will be fought in court and would start at about 10,000 or so at least.

This can vary by area. I've seen fees starting at $1500. So shop around.

Well we did some shoppin around and we found that it will cost about 1000 and much easier than I thought it would be than k you for your answers

Thanks for letting us know.