Morgan here from the Social Team at Shopify.
This sounds like a really great tool. I love that you've reached out to the forums for some feedback on your app as well. One thing I wanted to touch on, do you need to have a large bank of existing data/completed ads to have enough information for your app to be effective? If so, how much data is needed? Or, can the app be used/helpful for a businesses very first ad? Lastly, does the app just offer suggestions, or does it run/automate ads for you also?
The high recurring price point may be steep for a large percentage of small businesses. However, I don't doubt this app could be a great contribution to any business needing help with lowering ad cost and increasing sales. Have you considered a free trial, rather than a money back guarantee? You may see a larger number of businesses willing to try the service if they can test it without putting their money on the line, and then once they can't live without it they will be more inclined to pay the $99/month.
These are just my initial thoughts, but I'd definitely be interested to hear what others think as well!
Morgan | Shopify Social Team