Huawei covers are available on eBay and Amazon. While eBay acts as the middleman and puts you in contact with sellers that have Huawei covers available, Amazon both sells from its own stock and lets you buy from other sellers.
There are two ways to buy Huawei covers on eBay: You can either bid on auctions or buy covers at fixed prices by using the Buy It Now feature. Amazon only lists fixed prices, but you can get quotes from multiple sellers for both new and used covers. In addition, you can see customer reviews about covers you're considering purchasing on Amazon.