Using Spray Foam in Car Rust Holes Questions

My pickup truck has been lusting out for quite some time now. I need to put something in the rust holes because wind is coming up in the cab. in the winter it gets very cold because the wind shoots up in the whole. I also have another car with ross problem setting need a fix on. I’m just looking for a cheap fix because these cars are are ready gone too far. they’re not worth the money and time to fix because rob has a ready killed it.

I have been thinking about getting a can of spray foam and bring it in the hole of rust. I don’t see how it could hurt any at all. I just need something to block the whole as fast as possible. the truck is not nice but I wanted to look decent. is there anything wrong with using spray foam in the large hole of rust.

The spray foam stuff it’s cheaper that will help fill that hole of rocks. plus the whole world not lose it self pick up the phone will be in it. I feel the foam will help it all be held together.