Yeah, I think this is the worst period ever to start or complete a collection of Intellivision (or other brands).
But this makes the search harder (if you want to get a good ratio quality / price) and, at the end, more fun.
Referring to mind Strike, you can find minty games NIB sealed Intellivision inc here:
at 23€ ($28), shipping included.
Dunno if they ship to USA, it’s a German shop. I bought one copy, got it fast and really in perfect shape sealed. They have also other games, some of them at a very competitive price given the perfect conditions...