Let’s say you have a product or a service that you sell for $100.00. If you set up a Facebook ad that went to 1000 people and 5% clicked your ad those clicks cost you $1.00 apiece. So that is 50 people clicked the ad or you spent $50.00 to get those 50 clicks. Out of those 50, you had 25% request information about your product or 12 people.
Out of those 12, you were able to close 50% for your $100.00 product or in other words you spent $50.00 on an ad that you made $600.00.
How much should you budget be? Your ad cost per $100.00 sale is $8.33. I would say that based on the metrics you need to spend as much as possible.