Also another idea is to just ask at the local high schools and see if one of the varsity pitchers wants to earn some extra money coaching a little kid. My daughter did that for girls that age when she was in HS. We've done that with my kids in other sports and they respond really well to HS kids as both a coach and a mentor. The HS kids are usually thrilled with the spending money and the opportunity to be a mentor (and put it on their college apps). By MS, you probably want a more professional pitching coach, but at 8, I bet a HS girl would be good enough.