Is your trainer going to charge for a percentage of the sale? Most do, and that's a good motivator for finding a horse for you. A trainer found and brokered the sale of the horse I purchased this spring. She received a percentage of that sale. Another option would be for you to find horses you think are suitable, bring copies of the sales ads to her and have her pick which you should go look at, and pay her for her time to go with you.
Just an observation, but your last post suggests that perhaps you don't have the time to own a horse right now. Starting college in the fall is going to take a huge amount of time, and if you can't find the time in the summer to get to a lesson while not in school, then you may not have the time it takes to own a horse at the moment.