help with automation during the sale

[Beachbear1970]

What's the best website to act as my store, I currently use squarespace for my website and I get my business fro my owned and controlled Facebook Group of which I list my own items plus other people's items to keep the group fresh and more of a marketplace like ebay or Amazon or the many apps that are aval --- but I also have 1 Instagram and 2 Facebook pages that I want to start to use so that I can advertise on them and (I've seen this on other's businesses accounts whereas a black small circle displays over certain parts over the ad, buyers can click the black small circle which will take them to my site to complete the transition and plus hopefully the 'shopping cart' site will display other similar item they might want to purchase from me - plus I'm looking to automated as much of this business as possible as right now I am having to do all of the selling myself either via text of phone with takes a lot of time. I currently have over 150K followers on my Facebook dedicated group that I control - any advice or help would be great - here's my FB group: https://www.facebook.com/groups/cooperativepeople