Hi Kumar,
paid apps in ISVForce pay 15% revenue to Salesforce. In return the primary benefits that you get are:
Two (2) Enterprise Licenses for Salesforce to use for your company
Use of the Salesforce License Management App (LMA). The LMA gives you a way to manage licensing of your app for your customers
The opportunity to participate in paid advertising on the AppExchange
In addition two these two partner models, you can choose to use AppExchange Checkout.
If you choose to be an AppExchange Checkout partner, you will still pay a 15% revenue share plus a small per transaction fee. You will get the first two benefits above (2 licenses and use of the LMA). You will also get the ability to use AppExchange Checkout to automatically charge your customers credit cards for payment. This is a great option for low cost apps that are simple for customers to set-up on their own.
Thanks