Quick questions, i saw ESO is coming out 4/4/14

But how much is ESO costing us? I'm planning to go for the PC version, so is it $60?

Is there a monthly subscription?

$60 for the box (which you have to buy) and you get your first month free, after that you pay $15 a month on a monthly basis. There are going to be special offers (like 3 months for $30 as a common MMO example) but we do not know what they are yet.

The payment plan for ESO is not open for discussion on the forums right now.
When we get closer to release, and more details are revealed, we'll open the Official Payment threads again.