Hello, I wanted to buy some text link ads on websites like http://www.thepixellink.com/ or other sites that offer link/banner ads for a back link. I just wanted to make sure before I did it that it wasn't against google adsense TOS. Thanks
It's not specifically against AdSense TOS to purchase inbound links, as they're a legitimate source of traffic. Google in general do not like paid links.
Adsense can be quite awkward about using other ad programs. On any of my sites the only thing I have ever use with adsense is Amazon Affiliate.
How would google even know something is a paid link and not one you put in yourself? They would seem absolutely identical to a spider.