I am making a full texture set that is really basic, my problem is I have no textures bought ingame. When I sell a texture set or something like that to someone, would I generally zip the folder, upload it to my box.net account, and then PM them the link? Or do I need to use items bought via the torishop, add my textures to those items, then send them to the person who buys my textures?

You just have to upload the .zip containing all textures (.tga) ;)

i usually pack it into a .rar folder and send it per email.