I'm looking into buying a edger for the first time. I have somewhat of a tight budget. Is there any edger you can recommend to get me buy until I can buy a more expensive one? I have HD, TSC, Wal-Mart, Ace, True Value, and a Toro dealer in my town. Also, I've never used an edger, could you use them against curvy sidewalks too? If you can't how do you go about edging those?