> If you knew you didn't have the money to fairly pay for this designer's services, why ask?
By this equation, a startup without a lot of VC money wouldn't have a shot at hiring anyone great - and yet a startup needs great people. Put simply, if you want to make a lot of money at minimal risk, run far away from startups. Go work at a big tech company who's a money making machine, become employee 29751, and enjoy your biweekly paycheck which will come whether you work hard or not.
The equation at a startup is different. You have to love what you do, first and foremost. That's not measured in dollars, but not hating the place where you spend most of your non-sleeping hours is worth a lot. Secondly, you really have to believe in the company, and your impact on it. Without that, you'll value your equity at $0, and the financial side of things will wear on you (you will believe you're being paid unfairly).
Part of attracting great people is making sure they believe in you, and making sure you can provide a great work environment for them. The people who are strictly motivated by salary are probably not going to work out. There are still a lot of great people willing to take on some risk so long as it's something they believe in.