Nowadays you have millions of platforms on the market, offering everything, devs doing expensive services, repetitive jobs being done.
In the end a low cost app is a small application that is made to solve a single problem, but this single problem is solved in a way that generates savings for the client.
A good example of the concept of a low cost app, an alert that your e-commerce is out of sales, at first seems meaningless? Did you know that if a store goes 6 hours without selling the loss is huge? and a low cost app for 5 dollars can save that money? With less than 1% of the sales you can save the customer's revenue.
Low cost apps is a nice trend, as the sense of big and complex things increasingly makes less sense solve small problems in a genius way that scales if you can do it for thousands of people.
Understand as the concept of low cost app any technology with cheap code, that solves problems that is a slider, an app with database, but solve one give exist for millions.
A company that I really like that works this concept very well is theme forest that has been doing it for a few years, another company that does it well is the zappier people, I think they managed to pass the message low cost apps for the future!