What Iphone app should i invest in?

Ok, So i'm planning to save up my money (HARD EARNED) 3 MONTHS of hard labor LOL. Around $2500

Anyways I need good idea's of Iphone APPS, that you would pay for?

Something you would buy and price range thanks?

It has to be a simple app that you would use thanks no games thats too expensive 8k >.<

No trollz thanks.

Invest

Copy&past

dax0.blogspot.com/2012/12/is.html

check 3rd 4th link