I am from India, another poor country. For an average guy, $2 is valuable. I know people who live on less a $1/day. However thats 'average', remember it's a county of billion people.. In India, if you have internet, then you can surely afford to pay $2/year.
I too am am from India. There majority of indians are on facebook and whatsapp. they give a damn about discussing things with strangers. I have brought reddit gold for myself in the past, I have donated to several cough filesharing sites like cinema obscura and torrentday. $2 is about 120 INR... about 20 cups of cutting tea from a roadside vendor or about 12 cigarettes. If you go to a fancy coffee shop, this is the price of one coffee. So it is cheap... the only thing is that we are not used to paying for services. However, the value of sites like hubski, reddit etc is about the content that gets created. If, as others are suggesting, the site allows only paid users then the content that could come from some random user would be lost. It will become a small and boring club and ideas will become stale.