I bought a bike at Target. Nothing very expensive, about $70.
Well, the first day I rode it, there was a little 'click' which got louder and louder.
I called the store, they said no refund, only repairs. This was one day later.
Ok, so I take it in, I live there for ONE WEEK, when I pick it up, same problem. No change.
I must have taken it back 2-3 times. I called corporate. To no avail.
I finally got a refund, three weeks later. It involved some real anger at the store, and calling the manager a few names he felt quite uncomfortable with...

but it did work.
Never buying a bike there again.