Depends. Are they getting salary? A draw? How many estimates can they expect to do a day. Are there any other responsibilities they will have? Is this a full time job with benefits?
If it's straight up commission any sales person worth their salt can make a good living at 10% running 7-10 appointments a day. If your company can not generate that many leads then you are going to have to expect to pay at least a draw or salary plus a commission.