I'm looking for ways to promote my iPhone app, is there a way that I can let bloggers and reviewers test out the app without having to pay for it?
With iTunes you are given 50 promo codes for each update of your app, whether for iPhone or iPad. These codes can be used to give out to the press, bloggers, reviewers, or your friends and family to receive feedback.
Promo codes are a very valuable tool when you are promoting your mobile app, make sure to use them wisely.
You can access the promotional codes from your app's Version Details Page. Enter the number of codes you want to receive and then click continue.
It is a good idea to put these codes in an Excel spreadsheet to keep track of them, know which codes when to which media outlets so that you don't send the same code out to two separate people. That would look bad.
What about Android Apps?
For Android Apps, while there is no feature like this on Google Play, because Android Apps can be download outside of Google Play, you can simply upload your app to a server and then send a link out for users to download it for free. Again, it would be good practice to keep tabs on who you send the link out to, even using links that expire after a certain amount of time.