Simplest, Cost Effective Way to Run Power to Garage for Garage Door Opener

Hey All, I am a brand new home owner and always looking for ways to save money with all the new projects that are arising. For this one, I want to run power out to my garage. mainly just for the door opener, but also very occasional power tool use. I was thinking just putting a single outlet would be completely fine. I already have a GFCI outlet on the exterior of the house, and my thought was to just move that outlet 30 feet to the front corner of the garage by buying some UF 12/3, splicing into that existing wire, bury 2 feet under ground and come up into the front wall of the garage. Then just run an extension cord up to the door opener, and for any simple small use power tools I might need. Or could I then just get a standard outlet and interior wiring to add one additional outlet at my work bench? I had an electrician come out the other day, and he was wanting to start all the way back at the panel that is on the other side of the house, run 100-150 ft of Romex inside, then switch to THHN in PVC for the outdoor run and back to Romex in the garage. He hasn't got back to me with the quote yet, but by the sounds of it, I would be looking at several hundred dollars, whereas if i just buy the UF cable I would be under $50. What do you think? Is there any reason why I should not try it myself? I don't think I would be using enough to trip the current breaker, so the only other reason not to would be if it is unsafe? Thank you all in advance for your time and expertise!