I purchased a lamp at Home Depot without thinking it through all the way. I want to hang it above my sink but there is no electrical wiring in the wall there to hook it up. Is there a way to convert it from one that is electrically wired into the wall to having a long wire and plug it into an electrical outlet?
Sure, you could buy an extension cord, cut the end off and wire it to the socket. But you wouldn't have an on/off switch. You could buy a light socket which has a switch and replace the one on the fixture. Without seeing it that is about all I can tell you. Good luck.
Yes. If you don't know the answer to your question, I sure won't tell you how. Find an electrician or someone that understands it. It's fairly simple for one of those. The wires can be confusing as hell. Tell the person whether you want the outlet always hot, or only when you turn on the switch. Always hot permits usage of the outlet without turning on the light.
Of course. Just go back to HD and buy a plug. However if you have never worked with wiring I wouldn't recommend trying to do it yourself. The insulation has to be stripped off the ends and the bare wire wrapped around the two (or three) screws on the plug. If you get the ground wire on the wrong screw it will create a short circuit and trip the breaker (after a small display of sparks).