Thanks Pamela! I'll checkout Miva.
Shopify is expensive but it offers the 3P store.
Almost like Apple charging a premium for their App Store? Maybe!
Like I said, you have to pay the Shopify tax when you want to transition, if you're a small business. Hopefully soon, there may be a competitor.
Btw, checkout Swell (https://www.swell.is/) which offers similar experience to that of Shopify. And is cheaper!