Every action on Cryptokitties or any other NFT projects on ethereum network requires gas. Check out the gas prices at http://ethgasstation.info/ or just follow the recommended gas fee on your metamask.
Short answer: Negligible…
Not really important IMO, the gas fees is quite low and it doesn’t add much to the cost at all.
I think its around 0.0002Eth
gas fee as in gas to execute contract. should be little. its merely transfers code that is small bytes
Some NFT games are trying to implement zero gas fee or having to sign your metamask all the time. For those that are moving to Tron is even better because there will be no gas fee at all