Tinder is entitled to charge as much as they want to whoever they want as long as they're not discriminating against a protected class.

The free market resolution requires competition, though. There might be a reasonable case to be made that products that don't have comparable competition can't be priced in a way that exploits different customers by charging more for receiving the same service or good?

I don't think there's anything comparable to tinder that found be considered legitimate competition- match.com, Madison, adult friend finder, etc are operating in very different markets with very different tools and expectations.