Where can I get my best deals on DSLR lenses + accessories?

I have been shooting from my Nikon D3100 with a AF-S NIKKOR 18-55mm 3.5-5.6 (General Lens) for quite some time now. I'm starting to get better and more interested in photography. I really enjoy photographing my friends skiing (both during day and at night). I also enjoy Sunset and Sunrise, Urban and Macro photography.

What lenses do you think I should be investing in? I was thinking of buying a Zoom Lens (70-300) and then probably a prime lens.

Where should I be purchasing my lenses? I live in Canada and my parents are going down to the States in a few weeks so I could pick it up in either Country.

Any advice is greatly appreciated!

Amazon is usually the best, and most reliable (if you shop online). For skiing, a zoom lens is much needed, and so is a prime lens for low light/portraits.

Any store will do, really. I shop for major camera purchases at B&H Photo online. Even Best Buy might have a consumer 70-300 lens. Some local camera stores will match prices, so if you have a locally owned store, try them first. It is good to buy from local mom and pop stores when possible. If you order online from a US store, you may have to pay extra in shipping and/or taxes or duty. Another thing to think about is the warranty. I don't know how a Canadian warranty will be, but if you buy in the US, the warranty may not be any good in Canada. Or it may be. Again, I don't know, but it is something to check into before you buy from out of country.

Nikon has a newish "normal" prime for DX sensor, the 35mm f/1.8G. It is about $200 USD. If you like closeups, you might want a macro lens, like the Nikon 60mm f/2.8.It will not autofocus on your camera. For insects, the 105 f/2.8G AF-S would be great. And it will autofocus on your D3100. For landscape, an ultra wide angle. Nikon, Tamron, Sigma and Tokina all make lenses for your camera. You can consult the Nikon website to see which ones will autofocus, but they will have AF-S in the lens designation. If you have good vision, manual focus is not out of the question, although learning the technique takes some effort. My vision is no longer good enough. If you step up camera bodies in the future, you will probably get one with the motor built into the camera rather than the lens, thus being able to use any AF lens.

Have fun shopping!

Amazon or B&H