cost-cutting maneuver
A fumingly-sarcastic reference to a shamelessly "sneaky 'n' unethical" (and unfortunately very common!) "buy-pressure" strategy practiced at many hardware/specialty-supplies stores; the ploy consists of a staffperson's hacking off a length from a roll of bulk-product like rope, wire, hose, or cloth, and only **afterwards** informing the customer how much the product is priced per foot, hoping that said customer will then feel obligated to buy the piece "since it's already been cut off the roll".
I once had a totally pathetic "cost-cutting maneuver" tried on me at a bicycle-repair shop --- I needed a rear shift-cable, and so the clerk cut off my required length of cable from the store's bulk roll, without first telling me the super-steep per-foot price or asking me beforehand if I wanted to pay that much. It was only when he actually brought the "ringing up the sale" screen up on the computer that he revealed the astronomical amount that it was gonna cost me --- a whopping SEVEN DOLLARS AND CHANGE! --- for just three or four feet of the cable! Fortunately, I had the "bravery" to just look mildly shocked and hastily remark, "Eeeyewww... that's a lot more than I can afford --- thank you anyway, though. I'll just get one at WalMart instead." Hey, it wasn't MY fault if the salesman had created a harder-to-resell cut piece of cable --- I hadn't asked him to chop me off some of the cable yet, I'd just told him that I needed a replacement shifter-cable, so it wasn't my "responsibility" to now PAY for said cable! He should have told me beforehand how much it would cost per foot, and then asked me if I wanted to buy it before he'd actually hacked the length off the roll!