Before this gets way out of hand let me explain. First, this was back when I was an employee...not the shop owner.
Now for the cost involved: Layout time was 20 minutes, max, for the whole project. This was not high-end design, we're literally talking about cranking these things out while waiting on other jobs to cut. All the production was subbed out. Yard signs, full color, double sided were $45 with stakes, business cards were $12 per 1000, magnetics were $7.50 in digital prints mounted to $6 worth of magnet. We'd group several jobs together to save on shipping so shipping for all was about $10. That's around $70 for the whole shebang. Production on out end was mere minutes of mounting the decal on the magnetics.
That leaves $125 or so to cover overhead and labor.
It might have worked long term but there were several problems. The biggest problem was that me and the other design guy would get bored with just pumping them out and occassionally we'd have a couple of hours design time involved. Then you were dealing with lower end clients all the time who complained about the price regardless, who constantly tried to get a better price by asking how much it was with fewer signs or fewer card, and they would ALWAYS raise hell about the price when they called to reorder just signs or magnetics. ALWAYS.
It didn't take long to realize the whole scheme was doing nothing but bringing pain in the ass customers to the door for little money. There is a share of the market out there that's just not willing to spend much on advertising their business, I just don't want to cater to them any longer.