Is this base idea sufficient for a ground level, not attached to the house wooden patio?
A plain old cinder block will deteriorate within a matter of years. Use blocks designed for the purpose, or pour footings like you're supposed to, following code to the letter.

Concrete Deck Block:



Other than as being part of the railings, 2x4s don't belong anywhere in the construction of a deck.



I've never used these, but a key rule to follow would be placing them on undisturbed soil (don't add dirt back into the hole to make it level). Remove the sod and dig your hole as perfectly as possible.