You're only option for a solenoid that cheap is going to be [Ebay Link Removed] And you're going to have to be seriously patient.
I've got a used mouse solenoid you'd have to run inline(don't have to, but recommended) I could send you for about $20 bucks. You'd have to come up with a power supply though. (which I also happen to have...)
What would Honey Badger do?