how could i earn by Ads display on my site?

Question

i,e where do i get ads

Answer 1

Your question doesn't make a great deal of sense, do you mean how much could you earn, or how to do it?

You do it either by selling the ad space yourself, or signing up for a free ad publishing programme such as AdSense, Text Link Ads or Commission Junction.

https://www.google.com/adsense/
Text or image adverts. You earn either when someone clicks on an ad, or when an ad is shown.

http://www.text-link-ads.com/
Text based adverts, you earn for each click.

http://www.cj.com/
Affiliate marketing. Lots of options, generally you earn when a user clicks an ad and then buys something or signs up for a service at the destination site.

As to how much you could earn, that depends entirely on what market you are in and how much traffic you command, as well as how well you place your ads and integrate them with your content.