Why does everyone assume I'm rich or have a huge budget

There's your answer. Next time tell them you're working on a POS Duster and see if their attitude is different. I never brag on my car especially when I'm trying to buy something from someone.

A wise man once told me always make people think you're a poor broke bastard and they won't expect you to buy lunch!!

I try to only tell the details they need, however, when ordering my axles they asked me street or race and I said neither that it was a cruiser/pro touring build and they started talking full floater axles and quick change hubs and I was like whoa whoa I didn't say nascar.