I tried the "donate work to a charity" route once. I contacted many charities and offered to do work for free. I told them my motivation was to increase my portfolio and that there were no strings attached to the work, no ulterior motive or bait and switch tactic. I couldn't convince a single charity to accept free work. It turned out to be a very tough sell.

But there are other ways to beef up your portfolio. Why not just create your own websites. You'll need to pay the hosting fee and the domain registration fee, but those are relatively low costs.

Do you have a hobby you love? Build a site with information for enthusiasts. Is there a band, movie star or writer that you are particularly fond of? Build a fan site with pictures, a forum, etc.

Is there a cause you believe in? Are there products you really like?

The point is to create websites. Nothing will be better than to point a prospective client to a few completed websites. He doesn't have to know that you own them. All the client needs to see is the quality of your work in correctly functioning websites that he can surf to on the web. This will convince a prospective client that you can start with nothing and create a fully functional website.

Unless he asks for references ... then you can give him a song and dance about not wanting to give out that kind of information or something. Or just be honest and tell him that you own the websites he just reviewed.