Best dog food suited for Am. Staff Terriers? Questions

I am looking to get my Am. Staff Terriers on a healthy grain free diet. What brand of dog food best suits the breed along with being reasonably priced? My female is allergic to grain and my male has a hard time keeping weight on. All are under 2 years old. Any help and info will be greatly appreciated!

I'm sorry to say I don't know anything about Am staffs.
But I found the best food for my pugs that is grain free
Is Wainwrights wet and dry they have never looked better and I won't change.
It won't break the bank either.

Best diet for pretty much any dog is raw diet

I also feed Wainwrights Grain Free & wet trays with lots of additional veg. CSJ's 'No Grainer' is tripe based and has 23% fat, so is good for keeping or gaining weight. However, I think these products may not be available in the US - which is where I presume you are based. I'm sure someone with local knowledge will be along soon.
In the meantime, welcome to Breedia from Carole, Tweed and Eddie the Beagle.

Pereg and I welcome you to Breedia!

Taste Of The Wild is grain-free but I do not know whether it is reasonably priced or not. You can also check Canine Caviar.