The question too long to answer. Facebook ad budget depends upon your overall marketing budget. rnrnFor the testing purpose, I suggest using 10-15% of your overall budget for the campaign if it is possible. Run 2-4 different tests with $20-50 for each ad. rnrnOther than that, here are a few tips: rn - $5-10 per day for testingrn - Run your testing at least 4 days before arriving at any conclusion. rn - Keep optimizing at default settings as Facebook is doing a great job in it. There is no need to a bit manually. rn