A huge part of this problem comes down to how you’re perceived by potential clients. Factors that play into this are your reputation, your portfolio, how you talk about your services, the quality of your work, and your pricing.
When I first started out as a freelance web designer, I got some tire-kickers and low-ball clients. Everyone does when they’re new to the game. But I never get them anymore. And it’s not because those clients don’t exist anymore, it’s just that better clients are contacting me instead.
Because I’ve cultivated a reputation that brings in clients who value quality work, not just the cheapest price.
I say this to illustrate the fallacy that many creative professionals blame this situation entirely on bad clients — as if it’s a necessary evil of creative work that’s beyond their control. It isn’t. If you work hard to build up your reputation (and back it up with quality work), the cheapskates asking for free or discounted work vanish quite quickly.