I just want a deal on home page where the customer gets a random (mystery) discount from three options (40-30-20% off) it would be great if I could also adjust probability for each option and make the 40% more rare. Is there an app that will handle this or a way to set up a discount within Shopify to achieve this? Any help or suggestions is welcome as well as a simpler method as mine may be over complicated.
That sounds like a great idea! There is an affordable app called Spin-a-sale that costs $9.99/month that will accomplish exactly this. Feel free to check out their app demo here to see the app in action. I hope this helps. If there is anything else I can help you with, please let me know.