On a recent foray to the hardware store (another place I shouldn't be allowed free rein) I noticed that a savvy entrepreneur has marketed "Duck Tape" with a comic picture of a duck on the package. The "Duck Tape" is actually duct tape.
Duct tape -- for those not familiar with the product -is silver color on one side and has black sticky stuff on the other. Excellent not merely for its original purpose of sealing duct seams but also for repairing skis in an emergency, repairing a tear in a wet suit, securely wrapping packages, etc., etc. Also easy to tear off a strip without a knife or scissors.
Comparing prices and tape lengths, the regular old duct tape is much less $$ than the cleverly packaged "Duck Tape."
So, it appears the uninitiated in the mysteries of hardware spend twice what necesary because of a slip in pronunciation.