I work in marketing at a startup, and have worked at several in the past. I'm not sure what startups you've worked for that beg you to take their money - maybe

I work in marketing at a startup, and have worked at several in the past. I'm not sure what startups you've worked for that beg you to take their money - maybe I've been working for the wrong startups! I have, however, had startups pay me good sums of money for providing a skillset. Marketing at a startup is a different animal than marketing at a large corporation - you must be able to handle SEO, SEM, investor buzz, brand awareness, customer support (in many cases), audience research, and a general plan for pushing out the product. Your ability to 'cold-start' a product will be crucial - you'll need to figure out how to target early adopters, reach out to press, etc. Having a good rolo-dex of connections helps here. It's wrong that there's 'no demand' for marketing in startups, but it's hard to make blanket statements, as interest in early marketing depends on the type of the startup. Usually, UX/Graphic Design is hugely valuable. It's also important, however, to have at least some knowledge of the tech you're working with - it helps you make rational decisions and not recommend things that are technically near-impossible.