Thanks for posting your requirement
be precise in requirement .
Ladoo , free recharge , Free Mobile Recharge each application has general same scenario but a lot individual features that causes time frame and budget variation.
Quote for a regular application like this.
What we offer ::
Front end codes , Android studio
back end ,admin section , Sql
Material design ,work on above android 5.0 lollipop version (depend on your choice)
we worked on this kind of apps for clients.
General amount scenario attached below.
Thanks and regards
R.D