1. Check other similar roles online to see the going rate
2. Value your unique attributes, what sets you apart from everyone else and what value you would put on that
3. Force them to make the offer, don't play your hand
BUT, I would say, as much as money makes the world go round, a horrible job makes you forget the pay rise very quickly. Have you worked for a smaller company before? Bear in mind you will need to be more hands on, no HR, no IT, much less support, you might also experience more 'its my baby' from the owners. Jim made a good point, promises of high flying and the like are great, but any company big or small can claim that.
Think about why you are moving, are you unhappy where you are? Money will follow if you are in a happy environment doing a job you are passionate about.