Quality control with microfiber towels is a challenge. Even the top US dealers have a hard time getting consistently good quality towels from the mills in China and S. Korea. Buying from a well known supplier is key IMO. There is no method to easily determine a top quality towel from a poor quality one; most of us experienced detailers know by look, feel and performance.
While spending $20 on a dedicated towel may be extreme, I think you have to agree that buying at the lowest end of the price range is equally extreme. Online detailing suppliers have a great selection but you can find decent towels at Target, Walmart, etc. Warehouse clubs sell towels in bulk of acceptable, if inconsistent, quality.
The above thoughts apply to cotton terry towels as well.