"I haven't found anywhere on the site how much it will cost full total for the 2 year pre-paid."
You can view the 2 year pre-paid prices here.
"Also, do I pay $8 a month, or does that go towards the total itself over 2-some years?"
No, you pay one lump sum for the entire two years (if it is $8/month, that would be $192), that's the "pre" part of "pre-paid". They break the pricing for the 2 year pre-paid down to a per-month value in order to show the savings vs. the regular per-month plan.