It looks like the Wal-Mart price went up $3 since
this couple rode 4000 miles across the US in seven months on their $129 Wal-Mart bikes.
Here's a quote from their web site:
Over and over we heard, "those bikes aren't intended for anything but bike paths in the park, they're for sidewalks, not the open road," and, "they'll die on you in a couple of hundred miles, you don't know how to fix them, you'll get stranded in the middle of nowhere - what then?"
This wouldn't be the recommended way to do it, but it proves that with a bit of resourcefulness and determination you can tour on just about anything that rolls.