How many stripe merchants have dynamic billing descriptors enabled, or the equivalent of dynamic billing descriptor equivalents with on POS systems?

There are a couple that comes to mind. Check out Paddle.

If you're asking about processing point-of-sale payments, have you considered using the smart phone tools available from Square, PayPal or QuickBooks? You don't need to have a formal business entity structure to use these. A sole proprietorship is a viable business model to conduct some sales and test payments.

Such solutions are wiedly available to current ecommerce business. Question you would have to ask yourself if what makes your different, what is unique in your product that is not currently available. You are targeting (basically) 2 types of customers: 1. Those who already have a solution in place 2. THose who are opening their ecommerce business now (maybe due to COVID-19) situation. You need to have selling strategy for both. By that I mean they way you find them, make contact and explain to them painpoints that you are looking to solve if they were to implement your solution. Please also remember that when dealing with payment service, you are probably facing ton of regulations that you need to follow - I would be sure that you have that in place before you push further. Security angle is also very important. Good luck!

I don't think there's a best practice, similar to how much you should charge for your B2B SaaS company, cause it really depends on the market size, cost to deliver, and perceived monetary value you're offering via your API. That being said, the way I've baselined any pricing for my products has been to look at 100 companies that share similar customers and pricing model and either look on their website or email their sales team and ask directly. Even if you get 10% response that's enough to get you started.

Balanced Payments or Stripe