I spit at you for your reference.

Unlike conventional housing construction, which is practically free.

I estimate 500 USD per 50lb cartridge of concrete.

How much more if I want color?

I think for printing the actual face of the concrete you'll need the separate paintjet printer. It too costs an arm and a leg compared to a knucklehead with a brush but think of it: you could have Scrotum H. Vainglorious' ascii penis art collection as your wallpaper!

That is considerably more than an arm and a leg. That is more like an African White Rhino arm and a leg.

However, you'll wind up saving a lot by cutting out labor costs! ALL labor costs - including the cost of feeding, instructing, and monitoring the dysgenic biologicals who would otherwise have to be relied upon for building your concrete transhumanist pleasure palace.

You'll only be able to get these with a built-in space telescopes attached at 1150% the cost of both separately, and when a little sponge dries out in the casing it bricks itself, making you have to buy a new printer and space-telescope. Unless you want to collect dead printer husks and space telescopes.

All kidding aside, you could prolly drop rebar down into the slot and backfill with concrete. In fact, the whole "print" could be seen as a big mold, something you'd break off after the actual structural 'crete has been filled and set.

The real challenge would be doing the thing on site. A warehouse is an easy space to control, the great outdoors, not so much.

I'm not a engineer, but the way an engineer explained it to me, rebar wouldn't be necessary for something like this. Rebar provides strength against flexing and stretching forces which concrete is weak against. It's useful if you want to create things like beams or spans. These walls are going to mostly support their own weight and the weight of a roof, crushing forces that concrete is very strong against.

Concrete curing is not a drying process, but a chemical reaction in solution. I'm guessing the only way one can print like this is by keeping internal humidity at 100%, which must be hell on the workers (in warmer climes) and machinery.