In general, startups should think of business models that maximizes the lifetime value (LTV) for each customer they acquire - as well as business models that helps to create some level of predictability and repeatability.
For this reason, one-and-done strategies where you acquire a customer, they pay you once and you never see them again, is going to be very difficult - it can work if the transaction is very large in size and scope and you have a trained sales force to go after them in a direct sales strategy. This can be very difficult to sustain if you are attempting to sell products at a modest price to consumers.
In that case, you would be well advised to think about how you can come up with a recurring revenue stream, because that means you can predict a certain level of continuing revenue once you acquire a customer. For hardware products, if you can sell consumables, that's a classic way to generate a recurring revenue stream. For software products, subscription in a SaaS model is typical.
Anything can be made into a subscription. For example, if you sell pistachios, you can sell them in one or two ways: