See if you can buy "credits" in bulk, for example pay $100 at once to be used as you need it later.
Paying small amounts is unfortunately no longer possible, not only for you, but also for the receiving party, they have to pay the same fee to use your $20, meaning most of it is lost to them too.

For your own fees, best you can do is switch to SegWit, and consolidate your small inputs at low fee when you're not in a rush.