In addition to Google Play there are many other stores where Android applications and games can be purchased; Both free and paid versions. They are “legitimate” stores, that is, where what is paid, is paid. However, they can be interesting for various reasons. For example:
Amazon Apps: Usually give away a payment application every day. The bad thing is that sometimes they delay in putting the last version of the applications for more you can visit http://skimall.net/
F-Droid: catalogs only free and open source applications (opensource); So it is imperative if you want to support free software.
Yandex: is the most popular application store in Russia, although they use it worldwide and the application is in Spanish. It is good, they check all the applications with Kaspersky antivirus and, in addition, they give you bonuses for 10% of the amount of each application you buy.
But, in addition to the legitimate ones, there are numerous shops and sites that offer all kinds of free applications, both those that are already free and those that are originally paid. They are the most pirated Android stores on the Internet. And, of course, they are also very popular.
In them you can download all kinds of applications and games at zero cost. Sometimes, these are modified applications to remove the license check. In others, it is simply the pro application itself that is shared and it is enough to install it to make it work.
The possible negative part is that such modifications carry some kind of malware so you always have to put an extra attention (read permissions, for example and reject what is not quite clear).