Depending on the client and their app I see iOS/Android dev houses and individuals charging anywhere between $50 and $100 per hour.
Now, I think that both of these numbers are on the high-end. the $50 being for a dev house that has all their staff in india aside from some mgmt here in SF. The $100 being a dev in NYC who was a good dev, but not a designer.
Depending on your situation, interests and what you want to/need to make - I would go on the lower end to get more business (assuming you have need of more)
Also, I cant tell what exactly was required of you as a developer in creating these projects (I didn't look at them to see the architecture - but clearly you're connecting to services that have the data, and in the case of the music streamer - streaming the content)
How difficult were these for you to make? How many hours did these apps take you? What is your strength and weakness?
I think they look great.