I tried a few brands of this stuff when my brother was really into it.
In short, if you smoke weed, and still can, you won't want to bother. It tastes and smells terrible, weak high, and it's expensive as shit.
Someone above mentioned JWH. From what I understand, it's the chemical K2 and similar incenses are dipped in. It has a MUCH more synthetic taste to it - very chemically, but it does actually get you high, lasts a bit longer than k2, and is usually more bang for your buck.
As for aff programs, I get invites to join programs all the time. Just got one for liquid K2. So they are out there.