Ok, so I have been selling on Shopify for about 10 months now and I have accumulated revenue of more than $45,000+ through 2 Shopify stores, different niches. I am currently averaging $3,000 per store at the moment & christmas sales has been crazy. Bear in mind I live outside of the US but my main markets are South Africa & Dubai mostly because that is my targeted ad market. To my knowledge, Facebook ads dont really work like that, saturated and FB is strict. My best platform for ads has been Instagram (same facebook) which gives me at least 150,000 impressions, 900 clicks and at least a 10% conversion rate with a $25/4 day sponsored ad. Everything takes time so give yourself at least 10-20 days if you are lucky before you store becomes busy.
There are plugin apps that make sales better like the ones that pops up showing people shopping & adding to cart on your website, the fear of missing out. You can work on your instagram SEO like buy likes & followers and just know how to work the IG algorithm (post early between 7-10am, use locations, the right hashtags, etc). Adwords is the best for people to find you through Google ($80 a month is okay). Adwords Express is for non tech savvy people like me but has given me more conversions than any other platform. Shopify is easy, never once have they ever blocked me and if you are sick you can card your own store

Next year the plan is to have 10 more shopify stores so I can that Porsche waiting for me. I already bought an Audi A6 and have my apartment sorted since I started selling on Shopify. All in one year.
I hope this helps. Shoot me a message if you need help in setting up one. I can help with setting up your store, suppliers and anything thing Shopify related.