Just introducing myself, i'm Philip from www.OrionExchange.com, a 'Free Mobile Application Advertising Platform/Exchange', whereby you have two options:
1.) Install our SDK code to earn Credits. Every Ad served will earn you 1 Credit, which you can then use to Advertise in other Apps.
2.) Purchase Credits (packages starting from $2 to $550, you can purchase 1,000,000 impressions for $550!).
I won't write much about our service in this introduction because...it's just an introduction. I'll write a topic on OrionExchange later for your use though.
Thanks for reading.