I've been riding a Schwinn GTX-3 from Dick's Sporting Goods for the past 5 years. It has wear now but not overly expensive to replace some parts. Especially if one does the work themselves. I wouldn't be shy nor embarrassed to buy a Schwinn at Walmart for 2 or 3 hundred dollars. It's not like these bikes just fall apart just outside the door.
I'll tell you what I am embarrassed to say..... I bought a Specialized for $2000 when I could have bought a bike at Walmart that does the same thing as the Specialized for $250.!!! Truth. To the OP.... Think about that. Plenty of good bikes out there for under $500.