What To Look For
Crampons offer added stability on unstable surfaces, including scree, ice and shale. Aluminum crampons are lighter than steel ones, sometimes substantially so, and are a better choice for hikes over several days. Aluminum crampons do not keep a sharp edge the way steel crampons do, however, so they are less effective on rocky surfaces. If you plan on using your crampons on multiple surfaces, steel crampons are the best choice. If you plan to use your crampons strictly on ice, then aluminum crampons are lighter and just as effective.
As with many other pieces of outdoor equipment, some shoppers quickly become infatuated with a particular model or type of crampon and buy it regardless of whether it actually serves their purpose. Crampons are specifically designed for ice climbing, rough hiking or mountaineering, so make sure you get a pair designed for your particular activity. The difference in weight between steel and aluminum may seem negligible at the store, but it can make a great deal of difference after five days on the trail, so take weight differences, even those of only a few ounces, into account.
Where To Buy
If you are buying your first pair of crampons, buy them in person at an outdoor specialty shop. REI is an excellent choice, as their employees are trained to be knowledgeable in their particular departments. Mountaineering stores will also be able to help you with tips and advice. Be sure to bring along the pair of boots you plan to pair with your crampons.
Generally, crampons will run between $100 and $200 for a basic pair. Crampons can be found at specialty shops, of course, made of advanced materials, for much more, but for your first pair of crampons, regardless of whether they are steel or aluminum, you can expect to spend about $150.
Many serious outdoor adventurers wind up with a pair of both steel and aluminum crampons so they can match their equipment to the proper occasion. Clearly you won't want to carry both, but you can often take them to the trailhead and match your equipment to the situation and trail conditions.
REI will let you try out equipment before purchasing it. Particularly with 10 or 12 point crampons, personal preference is the greatest factor, so feel free to take your time and try a few out before making your final decision.