How to promote an iOS app?


I have recently developed two iOS games (Eye Jumper and Eye Breaker) and i am trying my best to promote them with a minimum budget. I think tried more or less everything there is (review sites, PRsites,..) but it doesn't really have a big effect on the downloads. I'd love some ideas or suggestions or even if anyone has a success story of their own on how to promote your app without spending a fortune. thx