Creating Customer Rewards

We shoot Gymnastics events, and sometimes the same families are at every event.  In order to encourage repeat purchases we were wanting to offer a discount for families that  changes with multiple min $50 purchases. 

For example
1 -$50 or more purchase =10 % discount on next order
2 -$50 or more purchase =20 % discount on next order
3-$50 or more purchase =30 % discount on next order
an so on.
I read that there is a way to offer price lists for individuals, which might be an option, but I want them to see the discount like it does when we offer a sale.  Is this a possiblity?  Or would I just have to let them know that there account sets the prices at a discount?

So I guess I am asking can we offer a sale  to individual accounts like the price list, or is there a way to offer this sort of discounts.  I have used the coupons before, but I dont know how I would limit it so it doesn't get shared, since I would have multiple families that qualify.

Any assitance or thoughts would be appreciated.

Create a new price list or duplicate an existing one.

Add a sale to that price list and assign it to the customer's account.