Unless you plan on using this card like 5+ times, Imp and Stargate are a hell of a lot better and don't take up a console slot. But... at only +1 MU, this card limits your ability to play cards like Stargate and Imp. So you're making a huge commitment to discarding a LOT of cards from your hand. Problem: most of the cards that you'd be discarding, are better than this card.
There's no price at which this would be a good card. It's asking a console slot for something which is provided more effectively and cheaply by cards that don't need the console spot or discards. 4 credits is way too high to consider this in standard. As long as Imp is available, I think $1 would be too much to pay for Carnivore.
Consider: Maw costs 6 credits and offers +2 MU and an okay trash ability, and it's probably overpriced relative to other consoles. (In particular, Keiko costs $3 for 2MU plus occasional $1 gains, and both of these play well with Stargate and Imp). If you wouldn't pay $6 for a 2-MU Maw which reaches into HQ and trashes cards on its own, don't pay $4 for 1-MU Carnivore which only affects cards you've already paid to see).