If you are looking for UV resistant PVC use the sch 80 grey electrical PVC. It is easy to find at hardware stores and building supply stores. The white UV rated PVC is used by the patio furniture places, some of them will sell PVC and fittings.

Using the primer greatly enhances the glue working properly. But i have used quite a bit of glue without primer and get away with it most of the time.

Someone else mentioned buying several small cans of cement and primer which is the way to go. As long as the can has not been opened it will stay good for years, i store it out side in the garage and i live in florida so it gets hot. If you want to check the condition of the contents with out opening the cans shake them. The primer is almost water thin so it sloshes(sorry for using such highly technical terms) around in the can easily, the regular glue is a little thicker so it doesn't slosh quite as well but you should still be able to easily hear and feel it slosh in the can. The PVC glues that can be used under water are fairly thick but you should still be able to feel it move around in the can when you shake it. If it doesn't slosh throw it out.

The threads on PVC fittings are molded which means that they do not always fit together well. Teflon tape will help, normaly two to three wraps is enough. Tightening the fittings by hand is not enough, wrenches on both sides of the fittings will be needed. If you want to make sure that it doesn't leak AFTER THE FITTING IS SCREWED TOGETHER place a bead of RTV silicone sealer over the joint where the two fittings meet. If you put RTV on the threads and then screw it together it will not leak, but you will not get the fitting back apart. When you need to remove the fitting peel off the RTV and then unscrew.