Old Metal Shirts
Those old heavy metal T-shirts you (or in my case my brother) wore in the 1980s and 1990s are now highly sought-after collectibles. Some are worth several thousands of dollars now and are worn by fashionistas like Kim Kardashian.
Old Beer Cans
Old beer cans are super trendy right now due to the resurgence on beer fanciness. Some cans are worth US$100, even without the beer in them.
Old Men’s Magazines
Old issues of men’s magazines, particularly Playboy, are now collector items. If you can find one in good condition with no pages stuck together (sic!) they can fetch upward of US$3,000.
Vintage Vacuum Cleaners
There is a large subculture (particular in the US) of grown adults who collect vacuum cleaners. Some of the vintage cleaners are worth a lot to these individuals. The king of the vacuums has a collection of over 300 hoovers.
As a father of young children, I have Lego all over the place, but apparently some certain pieces are worth a small fortune. Recently, a pink Duplo castle turret was sold for an astounding US$1,374.
Vintage cereal — sometimes even just the empty box is worth big money these days. In the 1980s and 1990s in the US there was a themed cereal for just about every TV sitcom from Alf to Steve Urkel. These are now serious collectable items and people are paying big money. Recently someone paid over US$200 for a 1988 cereal box with a Nintendo game theme.
Terrible Video Games and VHS movies
Video games that had exceptionally short lives due to being so awful are now so rare that collectors pay in bulk to get their hands on them. This is particularly true for old console games. Similar to bad movies that years later get a cult following, apparently so too do awful old video games and movies on VHS.
Old Happy Meal Toys — old junk
Old junk in general seems to be having a renaissance in perceived value. I personally blame the hipsters for this one. Everything from old knock-off action figures to happy-meal toys are now seen as the must have accessory for your man-child hipster cave. This includes old cell phones and even old empty packaging boxes, business cards and PEZ candy dispensers.