App development cost

How much does it cost to create streaming mobile app? For example like Periscope.

There are many factors that affect the price of development. Some of them are: complexities, features, human resources, iOS vs. Android development, etc. Here is good article for your question https://idapgroup.com/blog/live-stre...p-development/

Find out how to make a smartphone app and make it profitable. Best tips and tricks and practices from a well-experienced PM that will help achieve success.

https://theappsolutions.com/blog/development/how-to-estimate-basic-expenses-for-the-app/

Integrating live video in an app can offer benefits, like increasing user engagement and popularity by adding new methods of interaction to an app. Depending on your technical background or how far you've come with your app, mobile live video can be added in a matter of minutes.
Actually, you will need some broadcast technology to allow your app users to broadcast live video within your app from their device’s camera and some player to play the streams within your app, a website or a mobile device.
There are some sites, that do it all istead of you: bambuser, Iris Dev and https://theappsolutions.com/
Also, there are few starting steps
Choose Environment
Creating an Android app using Android Studio and Java
Creating an iOS app using Xcode and Objective C or Xcode and Swift 3

Hi guys!
Thank for your links! They're very informative, I've already saved some of them.
I can't tell you exact about Streaming Mobile App, because I've recently realized e-commerce app for mobile both Android and iOS. Nowadays digital marketplaces are shooting up like mushrooms, I hope that the development prices are similar, but it depends on many factors.

I agree with Bigive...