Since the question about store systems has probably been asked more often. Maybe it would make sense to offer an official plugin for this (for a fee). Currently, Merx is a bit too complicated for me personally, maybe there is a simpler solution here?
What does it mean simpler solution? I think the simplest is shopify or snipcart which can be intregrated quite easily.
Ecommerce is pretty complicated and maybe thats why Merx is complicated… its just hard.