Sochie :
I'm in same situation and was thinking cheap air cooler evo212 or something...
Then you're about $20 away from a far better cooler (one of the Cryorig coolers).
I'm still waiting for people to test the i7-8700 with the included cooler and find out noise results, however I'm fairly certain you'd get something like:
1) stock - fairly noisy under heavy load, and slightly audible in light usage (depending on how quiet your case fans etc are)
2) 212 EVO - quieter than stock, but still noticeable
3) $45 or so Cryorig (H7 Ultimate?) - virtually silent in light usage, and barely noticeable under heavy load
I'm not even sure what the Intel stock cooler is like. They at one point switched to a cheaper all-aluminum cooler so I don't know if they have a better cooler than this for the i7-8700 or not.
Also, don't forget to use the motherboard fan software to optimize the fan profile as it may be noisier than needed just using the BIOS presets.