Jam Auction Scam

How the scam works: (with video below) According to Wikipedia, in this scam the criminal "poses as a retail sales promoter, representing a manufacturer, distributor, or set of stores. The scam requires assistants to manage the purchases and money exchanges while the pitchman keeps the energy level up. Passersby are enticed to gather and listen to a pitchman standing near a mass of appealing products. The trickster entices by referring to the high-end products, but claims to be following rules that he must start with smaller items. The small items are described, and 'sold' for a token dollar amount - with as many audience participants as are interested each receiving an item. The pitchman makes an emotional appeal such as saying "Raise your hand if you're happy with your purchase" and when hands are raised, directs his associates to return everyone's money (they keep the product). This exchange is repeated with items of increasing value to establish the expectation of a pattern. Eventually, the pattern terminates by ending the 'auction' without reaching the high-value items, and stopping midway through a phase where the trickster retains the collected money from that round of purchases. Marks feel vaguely dissatisfied, but have goods in their possession, and the uplifting feeling of having demonstrated their own happiness several times. The marks do not realize that the total value of goods received is significantly less than the price paid in the final round. Auction/refund rounds may be interspersed with sales rounds that are not refunded, keeping marks off-balance and hopeful that the next round will refund.
How to avoid:

Always try to buy your desired products from official representatives, whether at an actual store or from a reputable website. Check to see if the business is legitimate. You can add the word 'scam' to your Google search, or just look for testimonials or forum posts that feature these products. Make sure the testimonials are from real people. Do not consider the ones that are posted on the product's website. A good research could save you a lot of money.