Test different prices in your sales

You could raise or lower the price in your ad copy. A higher price could increase the perceived value of your product and a lower price could lessen your product's value. Either way, you need to test which price will pull the most orders. Another idea would be to use an odd number like $19.46 instead of $19.99, $19.95 or $19.97. It makes it look like there is a specific reason you priced it like that.