like if I have 10 adgroups and I set all of them at max per day to 8 dollars....could it potentially charge me 80 dollars or a max of 8?
another thing is, is it ok to make alot of adgroups with only like 5 keyphrases each in each adgroup?
No, you pay per campaign. If the campaign is set at 10$/day max, you'll never collectively spend more than that much/day per month between all the adgroups in it. As far as a lot of adgroups, sure - you may indeed find that the more targetted your adgroups are, the better your CTR, CPC and QS score, and hopefully ROI will be as well. -T