I've purchased a couple of items recently that I've been happy with and thought I would share. Both are under $40 and worth the money.
First is the UPstrap camera strap. I'm late to the party here, but if you haven't heard of this yet, just go out and get one. There isn't a better no-slip, sling it over your shoulder camera strap on the market. I love this thing. You will find them at www.upstrap-pro.com. I bought the "SLR-Classic" for $32 + shipping. For a more in-depth third party review, check out this Luminous-Landscape Article. This thing doesn't even come close to slipping off your shoulder. I've walked the dogs while using it and not once did I feel like I had to reset the strap back on my shoulder to avoid having the camera fall...it just won't.
Second is a cool new item that is necessary in today's digital age: A depth of field calculator. In the old film days, there used to be no need for these things because the scales were available right on the lens. All you had to do was look at the marks on the scale that corresponded to your f-stop and immediately, you knew how much of the scene would be in focus.
But with digital, each sensor crop factor (1.3x, 1.6x, etc.) requires a different scale. That's why we no longer have scales on our lenses (a sacrifice for us full-frame 5D users who could have used the old scales). Well the makers of the Expodisc have provided a flexible and pocket sized solution. You definitely need to check this out. It's called the ExpoAperture2 Depth-of-Field Guide. I picked up one at my local camera shop (listed as a dealer on the Expodisc website) for $29.99. I can see where a portrait photograph would find this tool to be indispensable. After just two days with this little tool, I find I'm thinking much harder about my choice of aperture and the impact of distance-to-subject & lens focal length will have on my finished image. I could go on, but you just have to sit and play with this thing awhile to see how it starts the creative juices flowing.