Usually (for me atleast) you can get formula samples from your clinic. I know when I want to try new formulas I pretty much just ask my dietitian if I can try something new and she’ll just give me a load of things to try and I let her know what I like and what I don’t. nBre
I’m actually not sure how much the formulas are. I know they are expensive, but that’s all because here in Wisconsin we get out formula paid through the state, so my parents have never had to deal with paying for it.