That's in contradiction with your previous post 
My previous post had nothing to do with the current one. Not only that, the last thread discussing home gyms, I stated that it would be better to get your weight plates locally because of the cost of shipping.
It doesn't matter if you buy your weight plates used because its not an item with moving parts. Even if the weights are rusted, a little WD-40 and a brush will make them look as good as new. However you need to have a sturdy weight bench so you don't get a serious injury from it collapsing under your weight.
Some people will buy new and some people buy used equipment so if you're going to buy used, then you should know what to get and what not to get.