Little singles were not available for purchase in the first month.  Only people that upgraded jalapenos got little singles so there couldn't have been that many ordered within the first few months.

I used coinbase and they seem very good. Haven't had any problems with them. I also registered at campbx, but haven't made any transactions there yet. People say good things about them too though.

Is worth it to purchase ASICs right now?

what video card you using and what is your hash rate? if your hash rate is really low that could be why 0 shares are accepted.