A price of a few dollars a month makes some people suspicious, and that is reasonable. Cheap software is often abandoned software.
Here is the arithmetic. There is no sales team, no office, no funding to service and no marketing budget beyond this website. Payments are handled by a merchant of record who takes a percentage and handles tax compliance in every country we sell to. What is left funds the only expensive thing in the business: the time to keep the software working.
That is also the commitment the subscription buys. While you are paying, you get every update we ship and email support from the person who wrote the code. If we ever stop maintaining a product, we will say so on its page and stop charging for it, rather than leaving it quietly rotting in the catalogue while renewals keep going out.