We could probably guess your age based on whether or not you just recognized the phrase 'boogie boards.' These miniature surfboards - designed for bodyboarding as opposed to being stood upon - were briefly considered to be the next big thing in surfing during the 1990s, and every child going on a beach holiday absolutely insisted they had to have one. Australia, in particular, went for them in a big way - and that's also where the biggest market for second hand ones exists.
In some cases, depending on the condition of the board, the year of release and the manufacturer, an individual board can go for up to $10,000. Combining a few of them together into one set isn't a bad idea either if you want to attract buyers; a collection of 37 on eBay recently sold of $7,400. If they're doing nothing but taking up space in your garage, why not get them sold?