You can buy them online at places like Uline. The only problem is you have to buy five at a time.
You might try a local appliance store and see if they have anything they're throwing away. Or better yet, go to a local music store and see if they have any guitar boxes they are getting rid of.
You might want to use some foam or padding inside the case to keep it from breaking on the end near the strap button. The basses fit kind of loosely in those cases.
I have two that I'm cutting up / tossing tomorrow. You could come by my place if you want one and save me the hassle of chopping it up to meet local recycling requirements.
I have two that I'm cutting up / tossing tomorrow. You could come by my place if you want one and save me the hassle of chopping it up to meet local recycling requirements.