Hi I dont know about the prices in the USA but what I have seen they appear to me as exspensive as the UK
I was in the same mind as you but decided to build one as cheap as possible to see how it worked out. Make the mistacks on a cheap one and learn the pitfalls and there are plenty of them
My first one was a BEAREBONES with a case, motherboard and
psu
Then buy what you can from ebay dont lol you can get some good stuff and cheap and dont forget you can sell back on ebay when you feel that you are ready to spend a lot of money