I highly suggest against this, most tend to have a short battery life that grows shorter day by day over time. If you wanted to save your money and save yourself all the hassle of having the damn things dying on you every five minutes I'd purchase a reliable rechargeable battery kit, it's the same concept but they will last twice as long and their shelf life is 3x more than the Wii charger stations. This is all taking into account that you're buying a new Wii charging station, a used one will be even worse if it even manages to keep a charge for more then a few minutes.
Source: I have one of these charger stations.