Go to the event. The chairs are not sold at any stand featuring other wrestling merchandise. The only way to get them is by purchasing a seat close to the ring. The first five rows of fans in attendance actually get the chairs, so you need to be one of those lucky ticket holders to get yourself a chair.
Know that the easiest way to get the closest seats is by going to the box office the day that the tickets come on sale. Arenas will usually reserve a certain amount of close seats just for box office sales so even if there is a long line you will not have a problem getting a close seat.
If you cannot get a close seat or are not attending the event all together, then there are other ways that you can get a chair. One of the more official ways is by visiting the WWE Auctions website.
Here you will find a couple of left over chairs from pay per view events and the best part about these is that wrestlers usually sign them as well. You may spend a lot of time bidding though because these chairs could go for prices more than $500.
Another auction website to check out is EBay, which will allow you access to bid on older chairs like the 1994 King of the Ring and newer ones like Wrestlemania 24. The only problem with ordering at websites like these is the fact that you will have to pay a little extra for shipping as well.
You may also get lucky at yard sales, flea markets, or even hanging around the arena to see if any chairs are left over. You could come across one at anytime and if you do then hold on to that prized procession and piece of Wrestlemania history.