In Facebook, the more you invest the less you get back

[bsteve]

This might be hilarious to all the webmasters present here in this forum. But I would like to share some of my experiences with facebook recently. I started a campaign to get likes on my business page on facebook. Firstly, I invested about $10 just to test and I got back about 180 likes. So, in order to increase the rate I invested more at the second time it was about $20 and then I got about 300 likes. And on the third time when I increased the budget money again by $10 I got about 400 likes and not to mention the comments & shares are also varying very fast. Have guys noticed this kind of behavior of facebook?