Here's how the three major "get XX for [really cheap]" scams work.
Method A: The Matrix Method
You go to a website and pay $25 to get added to the matrix. After X number of people sign up after you, you get bumped to the top of the matrix and get the "prize". This is illegal and they usually collapse on themselves. The people you see running the auctions either A)Run the site themselves or B)are in the matrix and hope to get bumped up
Method B: The "freevideogames.com method"
You sign up for offers on a website (netting that website referral bonuses). This is stuff like price clubs, buyers cards, etc. You usually have to pay for a short trial period (ie: pay $1 for the first week in X club, after that it's $30/month), which is where the "PS2 for $20" comes from. There's big threads at fatwallet/DVDtalk about these kind of deals. Apparently they've gotten a lot harder to get the big ticket items. You also curse yourself to endless amounts of junk mail.
Method C: The "act like a buyer to foreign companies" method
You send letters to companies saying you want to start carrying their product but require a sample first. Any large company (ie: Sony) is already wise to this and won't bite. It's also illegal.
Of the three methods I listed, only Method B works, and even then it's so much screwing around I'd say just save up $150 and wait for Sony to drop the price of a PS2.
EDITBoth auctions you linked are the "Method B" type it looks like. Save yourself $2.75-6.50 and head over to DVDtalk.com and check out the forums there.