Yeah I've been doing fine with my $25 Costco folding chair - I just threw a soft couch pillow on the seat and try to remember to sit up straight. I think an Aeron could actually be annoying on a hardwood floor like I have at home, with the coaster wheels on the feet sliding all around.
Why not? I sit in a cheap chair. It's fine. I worked for a few weeks in a cheap director's chair once. It was fine; perfectly comfortable.