where do I put the batteries in the virtual boy?

In the battery pak which is attached to the controller (on the back of it.)

Yes, and if yours didn’t come with one, then you are S.O.L.

Yeah, be careful getting used VBs on ebay. Most people don’t tell you that the battery pack isn’t included (just like they say “I can’t test to see if the head unit works or not, I don’t know where the AC adaptor plugs in it”, when we all know it plugs into the CONTROLLER… sigh…).

Mine didn’t come with a battery pack, but fortunately it came with at 3rd party AC adaptor with a REALLY LONG cord! So I’m not complaining!