Where can I find a rear lens cap for my Nikkor 18-200mm?

Since I now have a second lens that I plan on using a lot, my 18-200mm won't be on my camera 24/7 like it currently is. I only have a cap to protect the front of it, I don't have one to protect the back. My new lens, the 50 1/8, comes with a cap for both front and back. My 18-200 didn't come with a rear cap.
I googled "Nikon 18-200mm Rear Lens Cap" and I keep seeing stuff about rear lens caps LF-1, 2, 3, and 4 and none of it makes any sense to me. How do I know which is the right one?

Try to put the rear lens cap of your new 50mm on 18-200mm, and don't be surprised if it fits!

Just use the end cap that comes on the 50mm. You ness one less end cap than you have lenses, because you will always leave one lens on the camera.

If you really want one, try a dealer or eBay.

The LF-4 apparently is an update from the LF-1 that originally shipped with the 18-200.

http://www.amazon.com/...0045TYDNC/

You can also get it for the same price at B&H, but I'm on an iPod and the link won't work on a PC.

You don't have a Canon. Any standard Nikon F-mount rear lens cover will fit.
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They are plentiful on ebay

Nikon back-caps are standard, so go to any good photo retailer.