Possible Clues:

• TV knife
• Product whose infomercial coined the phrase 'But wait ... there's more!'
• Kitchen knife type
• Supersharp knife
• Old infomercial knife
• Knife seen cutting tomatoes and pipes in TV ads
• Knife set available for the low, low price of $19.99 (act now!)
• Sharp-knife brand
• Kind of knife once touted in infomercials
• Knife type