Honestly, $10 is a steal!
At that price, we may stay longer than an hour. Hell, I may even buy a Tshirt if they sell them.
The park has a lot of custom imprinted items for sale this year. They did a complete revamp of their custom merchandise inventory and that does include shirts.
Last year when I was at the park they also had shot glasses and souvenir sports bottles among a ton of Blue Streak magnets. I saw pictures on Facebook of their merch this year and it's even more extensive so you should be able to find a few goodies.
They also sell a lot of collectibles from other parks. I stocked up on a bunch of somewhat vintage park brochures from all over for 25 cents a piece during my last visit. I have a huge brochure collection so it really made my day!