For group chat I much rely on ChatWing. Because by using this web based chat app I can easily communicate with lot of guys at the same time. Also ChatWing chat has the option for social media website as well. You can register on ChatWing using your Social Media accounts like- FB, LinkedIn, G+...
just tested the chatwing app builder and can confirm the app wizard available makes it straightforward to create an app. nice feature, the app supports Google admob ads so you can display banner ads and make money.
If you don't really know how much you should pay then you can take feedback from your relevant ones. Hope this will be much better to get a clear idea.