If all she'll be shooting is rimfires, you can get a swinger from Walmart for fairly cheap. It's one of the Champion swingers with a reset plate. I've only had mine on two putting with me, but it hasn't broken at all, after you shoot it, just hit it with some orange spray paint.
It does come with some bright stickers on the plates at first, but they get shot off in a hurry. I think I put about 100 rounds on mine so far with no issues.....that includes hits on the portions that aren't meant to be hit.