Simple store for Revolution

I am not new to MODx I have been installing this software on several websites over several years. With the help of the pros in these forums of course I know my way around with a little help, but am not proficient in PHP or sniplets without instruction.

Anyway, I attempted to add a store several years back (maybe 7 years ago) and at the time there were limited store plugins available in MODx. I know the store I attempted to implement was free, I am fairly sure it was shopkeeper. But I couldn't get the store configured. I just didn't know how to properly install it and gave up. If I recall correctly I had to add a bunch of sniplets from scratch which I thought was hard. Since then I just wrote MODx off for simple stores and sometimes use Wordpress when not using a dedicated cart since its so easy. Please don't slam me here, I know MODx is much better. Anyway, I can see all the plugins for stores but are any of these simple to install and use stores?

For my purposes the website doesn't need to collect or figure out shipping, just sign up (register) and pay for classes offered by this non-profit organization. So I suppose I need orders area, registration or accounts area, and to be able to attach payment like Paypal. Any of these stores pretty simple to implement with decent documentation? I don't mind paying a little for the store if its easier.

If not, I need to migrate a large website away from MODx. I really don't want to do this I just want to be sure if I stay and redesign from scratch I can get the store I need with MODx. Just a bit worried given my previous attempt so advice would be much appreciated. I would assume that the newer versions of the stores available now would have more features and be easier to implement than 7 years ago.

Actually, I would have to be able to charge 2 different prices for each class (product). One price for members and a different higher price for non-members. Visitors could check a box for member or non member like an option or attribute, as long as it charges more for non-members. That's the only unique feature.

In looking at shopkeeper again the demo and documentation or not in English. I think this was the issue I had last time.

I should have specified when I mentioned I don't mind paying for a cart. I don't mind paying a one time fee, but I don't want to pay every month like Foxycart or ecwin.

I'd try simplecart
https://www.modmore.com/simplecart/

Thank you. That seems to be exactly what I am looking for. One time payment, functionality, and simplicity. Wish there were a few more options, but I don't know Simplecart might work for different installation niche scenarios as well.