Online ads Start Up. Please Help With Advise

Hey guys, Please i need your candid advise and tips about my New start up. Am thinking of starting a business helping companies around me leverage the internet by providing for them online advertisement for there products and companies. The advertising is geographical though, Am from Nigeria and the target audience and geographical region is Nigeria. I have my business proposal ready but might not be the best, so i need your help too in that area. But my problem now is that, since am venturing only into online ads for this companies, i know of only Facebook ads and Google ads that can help me deliver this. But is there any other way i can do this ads thing at a lesser fee and the companies get productive results?

Am not really going out for the profit though, but i just want to offer a great service to my prospective client with a minimum investment cos i wouldn't want to bill them so much to scare them away.

Please guys help me with advise and tips and how to start up this online ads business. I will be moving form company to company, business to business.. I have a car to help me.

Please guys, am desperate for a change this 2015. I want to be financially active and FREE.
Thank everyone.