The simple fact that there's a store that sells. Also, that doesn't mean you can just buy the cheapest one they sell. There are a few essentials you should take into account before making a wakeboard purchase.
For starter's there's safety. Pros and novices alike must make safety a top priority. So, not only should a wakeboard be well suited to ones abilities, if you've saved a lot of money by shopping for discount wakeboards the money that was saved by not buying new should be put towards the purchase of a wakeboard vest.
Since we're already talking about safety, you'll also want to consider your skill level. Those new to the sport should be shopping for heavier boards with longer fins because they're more stable. Once the wakeboarder has had a chance to master some basic skills, then an upgrade to lighter, shorter boards can be considered. There's even the question of whether to opt for high rocker or low rocker, where rocker refers to the curvature of the board. Simply put, long wide boards with high rockers are best for beginners. Boards with lower rockers are really only suited to professionals.
All of the above choices explain why wakeboarding can be such an expensive sport. Beginners will probably have at least two wakeboards within their first year. That's yet another reason why shopping for discount wakeboards a wise decision.
Once you've picked out your new equipment, whether it's new or a discount wakeboard, you'll need to get a set of bindings. That's true even if you fit into the bindings already on the used board; or if the shop offers a set of free bindings, which are usually made cheaply and not terribly safe, it's a smart bet to get a new custom pair of bindings made. Each wakeboarder has their own unique level of comfort which is pretty important if you want to wakeboard for more than a few minutes without pain!
Last but not least, make sure not to let the price be your sole deciding factor. Whether it's discount wakeboards you've got your eyes on or you want a brand new one, you need to be sure that the board can support your weight, that it can hold up to your skill and above all, makes you excited to go out and pursue the sport with everything you've got!