I see a sealed GB Felix the Cat for $3,999 on eBay.  What is the general consensus for a sealed Felix? $2K? $3K?

Sealed GB games have fluctuated a lot since I started going for a cart-only set in 2016. Even though I just want carts, I still pay attention. To be honest, I think the only people buying this stuff is people wanting to get full sets and I highly doubt many people are looking for this game. It is a moderate/high priced title but in it's standings of value, compared to other games, it's slipped in ranks over the years.

I can't give you a straight answer. Best I can say is list it for auction and see where it goes. Maybe you'll get $2,500 (I'd be shocked) or maybe you'll only get $300 (more likely if no on is looking for it.). You just can't tell because I don't think deep pockets are looking for most of these semi-rare GB titles.

I can't see this even breaking $800 in anytime of GB collecting time.

Depends on print too. Hudson Soft is where it's at.