In the current business environment, the best way to deal with customers who can’t afford your service is to be creative with your pricing model and come up with a solution that they can afford or at least a win-win situation.
Here is an example.
Netflix offers a subscription you can get out of at any time. The monthly subscription is easier for everyone to pay rather than a lump sum. They also offer different levels of subscription so subscribers can make a selection based on what they can afford and feel the service is worth to them without going down the illegal download route. A win-win situation.
Another example is Microsoft Office. A few years back many Microsoft users could no longer afford to purchase software as a once-off payment. The high costs encouraged piracy or adoption of open source options causing significant losses for Microsoft. A win-win situation today is Microsoft offering their up to date software on an affordable subscription basis.