Lots of good bikes in the $300-500 range. I've had one for more than 12 years and thousands of miles without issue or drama.
I paid $300 for a single speed road bike from BD in 2012, it looks fancier than it is with a carbon fiber fork. Added some Gatorskin tires and it's worked ever since, I only clean and lube the chain every 5 years so far. Made in Canadia.