You can look for a used one. I know of at least one shop in the DC area that has used folders. If you are in that area, let me know and I'll give you the name.

Bike Fridays are expensive but they are really nice. The Tikit would be perfect for the rides you describe, but they are pricey new. They are probably pricey used, too, because they haven't been out for a while.

I had a Dahon but it didn't fit my needs it so I sold it--so you see, there are used ones out there.