I have been considering purchasing the cheap filament on eBay for some time now. It's just so tempting. I have seen prices as low as $12.99 per roll at some points. However, I just saw this guy on google+ post that he ordered a roll of filament from ebay for $19.99. Guess what happened.... The plastic wrap that was covering the roll of filament somehow reacted with the material in the filament and pretty much destroyed it. It actually appears as though the plastic wrapped burnt right through the filament strips.

He bought this stuff (http://www.ebay.de/itm/271427502743). He was offered a full refund and he claims that only the top layer was effected and the rest of it printed fairly well.

Just goes to show you that cheap isn't always the answer.