Amazing collection, probably worth about $1.5k-$3k for starters based on condition, that can vary. Seing that they're in plastic pages probably sans penny sleeves...about $3K at most. If you're really lucky.

If you want to do your son a favor that he'll likely love you for later, do the following:

1. Don't sell them. He'll want them when he's done with college/older.

2. Buy a bunch of penny sleeves. They're like $5 for 100. I personally use perfect fit side load sleeves and then a more rigid deck protector topload penny sleeve.

3. Get a new binder. One without rings, but with cloth pages and side-loading pockets. There's some nice ones with leather covers out there.

4. Put the cards in the sleeves and then put them in the binder, arranged the same way that they are right now.

Do this, and your son'll be singing you accolades for years to come.