Fair price for dual exhaust?

[C15_Sierra]

I'm looking to get a true dual, H-pipe, 2.5" system with 45-degree turndowns right behind the rear wheels. I already have the mufflers and ball flanges, I only need tubing and welding. I called on a couple shops locally and they quoted me $400+ each. I also talked to a guy in Western Mass who'd do it for $300 over the phone, and a friend from work can tow it up there for me.

I feel like it should be pretty simple and easy labor since there's no old exhaust to take out and there's no rust on the truck...

Are those prices fair? Just want to be sure all my bases are covered

Thanks!