There are two types of startups - those with good funding and those without.
The first type has venture capital funding or some such. They have a lot of cash but there are external people who watch the books and demand progress. This sort of startup should be able to pay you appropriately, though probably not luxuriously. The days of excess ended with the tech crash of 2001.
The second type will be much tighter on money. The owner (and some pals) have self-funded. Think carefully about joining such a company if you can't afford to be unemployed at the drop of a hat. If they can't get funding it usually means the idea is half-baked. If they won't ask for funding it usually means the idea is half-baked.
Otherwise, startups usually have the advantages of exciting work, flex-time, telecommuting possibilities, and a casual work environment. They have the disadvantages of lots of overtime, people wear many hats, and there's a lot of unemployment risk.
You deserve your full salary because you're doing the work of someone with your knowledge and experience. You deserve vacation time because well, everyone gets vacation time. You deserve stock options because you're tolerating tremendous risk and working long hours. If they can't afford these things then their business model isn't realistic.
In return you're going to happily work yourself to death, accomplish the impossible, not going to complain, do what they want not what they ask for, keep them from dorking themselves technologically, and otherwise be a total team player. They won't want a doormat, they want your brain.
I work for a well-funded startup. It isn't easy but if we hit, my house is paid for. I give this a 50/50. If we really hit, I can retire. There's little chance of that, of course. But I knew that when I came on board.
But if you want it / Then you must find it
But when you have it / There'll be no need for it