A flat rate is a fixed price for unlimited or generously bounded use within a period. The customer pays the same amount whether they use the service once or fifty times. It removes the fear of a surprise bill, and it gives you predictable revenue, as long as heavy users do not cost more than they pay.
Gyms, mobile tariffs and streaming subscriptions all run on flat rates. The customer buys the freedom not to count.
The risk is the usage mix. Take a gym charging 30 euros a month with 1,000 members, where each visit costs 2 euros in cleaning, energy and staff. If 900 members come 4 times a month, they cost 7,200 euros. If 100 members come 20 times a month, they cost 4,000 euros. Revenue is 30,000 euros, variable costs are 11,200 euros, and 18,800 euros remain for rent, equipment and salaries. Now change the mix: if half the members trained 20 times, variable costs would rise to 24,000 euros and only 6,000 euros would be left. The price did not change, only the behaviour.
Flat rates attract exactly the customers who cost the most, because people who plan to use a service intensively choose them on purpose. That is normal, not a failure. You have to price for the mix you will end up with, not the one you have on day one.
Most providers keep a limit and call it fair use: a data cap after which speed drops, a maximum number of tickets per month, one user per account. State the limit in plain words. A flat rate advertised as unlimited and then throttled produces complaints and refunds.
Flat rates also cost you information. When everyone pays the same, the invoice does not show who gets value, so measure usage separately and watch the low-usage customers. They cancel first. In a generated business plan the flat rate appears as one revenue option next to pay-per-use.
