Is there a substantial difference in cost and if so which is cheaper?

It is estimated that a precast concrete wall uses 55% less concrete in the foundation than a typical concrete block wall.

cost of Block wall vs Pre-cast Concrete - Google Search

Sorry there isn't that much information -- I checked out many sites but didn't see a good answer

Even in pre-form concrete cast walls ( used in parking decks, commercial construction and other use) it is about still about 1/2 the cost. We have several pre=form concrete manufactors in Atlanta that make pre made concrete walls.

Consider the cost of one cement block to be in the $1 each range and you'll easily see that precast is much cheaper.

Precast is cheaper and faster