There are many sets of quality wheels, including some in the range of $300 or less, here:

https://www.retro-gression.com/collections/wheels-wheelsets

I have a set of Velocity Deep V rims (with machined sidewalls) on a bike that I ride almost daily. They're good. Very strong and pretty aero, but kind of heavy.

What kind of riding are you doing? Race track? Easy pace on smooth roads? Thirty miles a day including hills at vigorous pace? Do you cross lots of railroad tracks and like to bunny hop curbs, or baby your bike? Are you 130 pounds or 330? These are all important considerations when choosing wheels.