Rusty wheel boxes at the back of my Ford Escort

Hello, I have a Ford Escort year 94. 90 HP. I wanted to ask I should have my wheel boxes welded back because of rust. Well, I wanted to ask now what it would cost about that. I know that there are all these wheel wheels. And I also know what they cost. I would only like to know what the welding works cost. And my longitudinal beams behind are heavily rusted, but I don’t think they’re enough. Should I do that?. For your answers many thanks in advance.