Startups can be awesome but they can be a nightmare as well. I have worked with startups on an equity basis and a paid basis. I learned never to cut myself too cheap for them or they will take full advantage and leave you sitting in the gutter hoping they drop off the check they promised. Vet them heavily before you start, and not just the idea and company, vet the owners. Google them, research their past dealings. I have been burned by some very seemingly good honest church going folk that were really wolves in sheep's clothing. I love and despise startups for these reasons. They can be fun and exciting and you get to make an immediate and long-term impact so don't let me be a Debbie Downer, just be careful.