I bought a little Ryobi years ago at Home Depot or Lowe's can't remember exactly which. I think it was 18 volt and it ran right around a half hour. I'm thinking it was right around 75 bucks? After the battery died I bought a couple aftermarket on Amazon that worked well.
My GF is pretty petite so when I started dating her I gave her the Ryobi. It's small and light. Sounds like it might work for you. Sorry I can't give you a model or anything but if you do a search I'm sure you can find one or one similar.
