If you're considering running a power lineunderground through your yard, you have four options. Your choice depends on how much power you want. It also depends on your soil type—if it's sandy and easy to dig, save money by digging deep (you won't need to use metal conduit). If it's rocky or clay, keep your digging to a minimum. http://www.familyhandyman.com/electrical/wiring/how-to-bury-underground-cable/view-all
You can save a lot of money by doing your own wiring. Here we'll show you to wire an entire room. Even if you've never picked up an electrical tool in your life, you can safely rough-in wiring by following the directions in this article. You'll learn all of the pro techniques for a wiring job, including choosing the right size receptacle boxes, running cable throughout the room, and making the electrical connections.