Would the apps on my phone cost any money?

[SMMMIITT]

I got a Samsung galaxy young about two weeks ago and i downloaded a yahoo and facebook app about three days ago which for free but i'm thinking that
it might cost alot everytime i use it, does it cost money every time i use yahoo and the other apps even though it's for free?

[DnB925Art]

Many apps you can download are free. The two apps you mentioned do not cost you anything to download, however it may cost you depending on the data plan you have for your phone. If you are on a capped/tiered mobile data plan, the more you use certain apps, the more data you use. You use too much data, you get charged for going over your allotment on some plans. Try to use WIFI as much as possible to save your mobile data allotment.