App Development- Source Codes

i need someone who can do the following

make small changes to apps
add my own advertisements to apps
know where i can get advertisements from for my apps
upload apps to my stores
knows about making apps profitable

i will be doing multiple apps so if you can give me a price PER app so i can know i can continuously work with you … you will NOT be creating apps i will be buying app source codes and you will make small changes like names/ads/thumbnail etc