How big do you want the trees to be? They get exponentially more expensive as they get bigger.
You can get small trees for about $100-150 each, but I think you may be interested in larger trees, which would be more like $250-500 or more each.
We just lost almost all our mature hardwoods in April, and bought 5 trees to replace them. Retail cost was $2200.

That was including delivery but NOT including planting, which was another $150 or so. And that was just to have the holes dug. DH and I planted them ourselves, and that was a big mistake. It took about 2 hours just to plant one (they weighed over 500lbs each) and I thought we were going to kill ourselves.
I'm thinking what you are talking about would run at least $3000-6000. Maybe more. Go check out a local nursery and see what the size tree you think would work costs.
Or better yet, see if you could put a "tree allowance" into your selling price, so the buyer could choose the trees they like.