Pay-to-play, all the way for this art-fair scam. Artists are required to sell 20 tickets at $15-$20 each to show their work. Any unsold tickets are the responsibility of the artist to pay for if they want their work shown.
These shindigs usually include live music (bands who are lured into participating with the same ticket-selling scheme). So RAW offers a club (or other venue) owner free entertainment for the use of their venue for this “event”. The venues can charge a cover, and charge as they normally would for drinks, etc. and keep the profits, so they love the idea.
Read thru their FAQ and judge for yourself. https://www.rawartists.org/faqs