We made this mistake on our last startup, we got a ton of feedback saying, oh it's too expensive, I'd never use it.. make something cheaper/free.
The truth is... until those businesses are making more money that justifies $20 a month, you probably don't want them as customers... they will take up a TON of time, with adding little to no value and will have no problem jumping ship when you say, hey, you reached the size you said you were interested in paying $20 and we would like you to upgrade.
People want the world... focus on customers that find $20/month to be a huge value to them.