A good welder is not gonna be cheap, so you will have to make a compromise.
You may be fortunate enough to find someone with the skill and experience to do it right at a decent price.
The problem is there are hundreds of thousands of welders out there, but only several thousand throughout the country that can do it the right way.
I was a pipe welder in chemical plants for around 15 years. About 75% of the work we did was with 304L, and 316L stainless, and a lot of AL6XN.
It was still a bit different doing sanitary level welding coming from a chemical industry.
I had the skill just lacked the knowledge in sanitary welding.
I now do side work for barter with a local brewery. They pay me in equipment for my homebrew set-up for my services. I work cheap, but I still like what I do after all these years.
So you may find someone like me that can "hook you up"
If we were closer I would be glad to do the work for you.