Self-help, instructional, and personal training series have been popular for decades, and that didn't change with the advent of the VHS tape. Today, self-improvement tape series can go for exorbitant amounts for a complete set. A set of Vidal Sassoon instructional tapes on haircutting recently went for $150 on eBay. Martha Stewart instructional tapes are always popular, bringing in $20-$30 each. What about those VHS tapes that teach you to be a better salesperson, real estate agent, or ninja? Yep, they can sell for up to $200. You can even learn to fly with a private pilot VHS course for $50.