Trondei
I do the bidding for 4chan ads at the minimum amount, more sets it as priority over other ads as far as I know. I dont have a 'timeframe' as such so I just leave it to the minimum.
You can choose the format and position: mobile/desktop and header/footer.
you can choose the boards to target and the countries
then after uploading and naming it, you just wait for it to be approved, £20 minimum for a campaign