Opencart is free. You need to pay some modules you may need, but the simple shoppingcart system is free. Of course you need to know how to instal it to your domain or have someone do it for you. It is pretty flexible in terms of lay-out and other functions, but certainly different thing compared to all these places designed to be simple and easy and ready-to-go.
Paypal account suspension is old news. Wide variety of underground labels and people have been targets of action and I keep amazed that people do not know that. Or know the rules. Or know what it means if you do not follow those rules, even if they seem petty and random.
Small labels have no chance. Paypal values more their "PR" than modest money they make on small business. Big companies seems to have more flexibility. Those who think it only affects the "bad people" doing "bad things" are soon probably seeing that it's like business that operates soon in sensitivity level related to social media.
I know some bigger labels are now programming new systems where part of the inventory is not available for paypal, and others are. And some stuff is visible for casual visitors, others can be only seen by customers who log in. Just trying to figure out how to not offend every dork that visits their business, and not step on paypal's toes, and also keep the customers who came to buy some interesting and juicy heavy metal. I am pretty sure that eventually it will just lead to social media doxing campaigns. "I logged in and look what I found!" + screen captures of whatever that one feels entitled to be upset about.
It is unfortunate state of underground art, that biggest corporations in the world and handling the platforms of sales, promotion and communication and implementing regulations that seemingly already affect the art itself.
If back in the day someone would have suggested future underground is in leash of multinational corporations to this extent, one would have not believed. I would advocate privately owned forums, personal websites, magazines, distributions. Industrial music for industrial people.