I recently found a Lego-clone (not a very good one) at a discount store.
The pieces include bricks, 1/2-height plates, and a few wheels and
medium-slope roof pieces, in about 10 different colors. They are
slightly larger than regular Lego bricks -- maybe 10% larger, and of
course they don't interlock with Lego. There is no brand name or
trademark on the pieces; the packages say "Educational Toy, Regent
Products Corp. River Grove, IL 60171, G16096, Made in China."
I posted a pair of these packages (about 160 pieces) for auction at
eBay this week, starting at $4.95. The auction page includes a more
detailed description and a few photos.