Yes, I've seen them at Walgreens for $8 (though it's been a few years).
One of the biggest arguments my husband and I ever had at a theme park was when I bought each of my sons a $20 battery operated spray bottle with fan. :P He thought that was nuts. And it was!
Another fun thing to do is go to the Walmart close to Disney. If I remember correctly they have a big Disney section with lots of stuff, and it's much cheaper than the theme park items.
Good luck and hope you guys have a wonderful time! How awesome!!!
ETA: Now that I think about it I think Mandy is right . . . check Walgreens and other stores in Orlando too. I'm not a huge fan of Walmart (ugh) but I did like their Disney section.