im being asked to purchase some games that are free on google play

[AC Question]

I haven't changed anything on my phone but it's asking me to pay for free apps that I'm getting from Google Play

 

[B. Diddy]

Welcome to Android Central! Can you give more details? Did you install free apps that are now asking you to pay? This may be due to the "free" apps being trial versions only--read the app description carefully.

Or are you getting popups advertising certain apps? If so, then it's either due to the website you're visiting on the browser, or you inadvertently installed some adware (probably alongside some other game).