There is no place in the US that requires a permit/license for paintball markers.
There are no permits for paintball guns.
Yes most kmarts do sell paintball guns
No, they do not sell them.
Yes it does.
No. Direct buy is a funiture store therefore they have no need to sell paintball goods. try look for local paintball stores or even online.
Paintball pro shops are the best place to get them, however there are many websites that sell them cheap. Some good sites are Paintball gateway, ansgear, and zephyrpaintball. Some sporting and outdoor stores sell markers, but they are ususally beginner packs and other low end guns.
Zephyr Paintball manufacture all things to do with paintballing. On their website they sell paintball guns and accessories, clothing, protective gear and loaders at cheap prices.
There are numerous sites to sell your old and used paintball guns. This includes, Ebay, Pbnation, and Sellmygun.com. Though be warned, you could get ripped off easily.
i would suggest airsplat.com. even though they sell more airsoft than paintball, it is still good.
You can buy Spyder paintball guns anywhere on the internet. It is good to purchase from stores that sell outdoor equipment such as Sporting Goods or Dicks Sporting. You can also try Amazon or Ebay.