Well, in a nutshell - the two most important factors you should be looking for are the waterproof rating and breathability rating of the shell fabric. They are expressed most usually as '000s eg. a waterproof rating of 10000 and breathability of 8000. Any decent jacket (or pant for that matter) worth its salt is going to be at least 5-8000 in each regard, but can go all the way up to around 20 000 for top range stuff.
Insulation is also a big part - some jackets consist of simply the bare outer shell with no insulation save a mesh lining, whereas others will pack insulation in between the shell and the liner. Less insulation is more versatile, as you have the option of layering up underneath to control your body temperature.
In terms of features, again a decent jacket will have a powder guard (an inner section designed to keep snow from getting in your jacket); ventilation zips, a detachable hood, fleece lined pockets and a few well placed pockets for assorted essentials. Other than that, it really depends on fit and the style/design/graphic of each jacket. Buying something with quality outer fabric really is the most important part.
I bought a pair of new pants in California a few months ago for a great price - $109 with a 20 000mm waterproof rating. Other than that, I can't really help you out with prices. Check some of the online stores like rei.com for prices.