Well there are a couple you can use.
One is
Gaming Lagoon. This, site, unlike your site, allows you to complete free offers and surveys (though there are still payment offers if you want to do those too..). Basically, each full point represents $1. Once you have enough, you can go to the prizes section and choose "Custom Order" and order anything VG-related. This includes games themselves, of course, so you can just give them the link to an online store that is selling the game you want and tell them which shipping you want (based on the number of points you have that can cover it, of course) and they'll get right on it.
The other site is
VideoGame Lagoon. This one focuses just on the videogames themselves and is part of the same ring as my other suggestion. The main difference is that when you want to order a videogame from them, they go by price ranges such as "Any game $24.99 or under," "Any game $30.00 or under," and so on and so on (they stop at $80). The other thing is that they will only buy them from Amazon.com if you choose that method. However, they also have the "custom order option" if you want to do that there.
These are both great options, IMO and are definitely legit (when you give them your REAL info when you sign up, they'll call the number you give them shortly after you ask for verification to make sure you're being honest--so no dummy accounts!). All I ask is that you please use my referral link if you decide to join because that's what awesome people do. You want to be awesome, don't you?
Also, if you have any other questions, PM me.
