I saw those on ebay too. There are two deal-killers with those bikes:

1) $50 in shipping; it doesn't cost them anywhere NEAR that much to ship them. That's probably an extra $30 profit for them.

2) The small-diameter seat posts mean that they don't extend far enough to let you get good leverage when pedaling. If you can't get good leg extension, the deal's off.

I almost bought my wife the Schwinn hide-a-way on amazon, but wasn't sure about the seat post diameter, so I ponied up the extra money and got her a Dahon Speed P7. We'd both had cheaper Chinese folders in the past, and that short, small diameter seat post was just poop.

Oh, both of ours also had rear suspension. I felt like it was absorbing about 30% of my pedaling energy, but it was a nice ride.