What To Look For
Camping pads come in various styles from inexpensive foam mats to ultralight, insulated inflatables to large, thick air mattresses. Size is going to be your first consideration. Most pads will easily fit into a tent, but larger air mattresses may not. Also make sure the pad is large enough to comfortably fit you from at least your feet to your lower backside. If weight and space are issues, as they are for backpacking, look at the packed size of the mat and its weight. If you want to minimize the weight you carry, 3/4-length pads cut length off the pad without compromising much comfort. Tapered pads also help to cut a little unnecessary weight and size.
For camping in winter, or cooler times during the year, you'll want an insulated pad. Compare the R-value of the pad, which is basically its ability to insulate. Higher R-values keep you warmer. Sleeping pads generally fall in the 1 to 8 range.
Before committing to a pad, be sure that you identify exactly what you're using it for. Large, heavy pads or mattresses that require pumps are poor choices for backpacking, but for car camping, you may want to have a larger, more comfortable mattress. If you're looking for a mat to handle both car camping and backpacking, consider an inflatable pad that packs up small.
Where To Buy
You can find camping pads at a wide variety of stores. For the best collection of quality foam and inflatable pads for camping and backpacking, shop at an outdoor sporting goods retailer, either online or in town. You can compare the primary specs of a camping pad online and make an educated decision on your purchase without needing to try it before you buy it, though it never hurts to get your hands on it first. Some good retailers for camping pads include REI, Backcountry.com and Trails.com.
Camping pads have a wide price range. Simple, foam mats can be found for $25 to $40, whereas lightweight, inflatable pads typically cost from $75 to $200. Car-camping air mattresses generally cost between $50 and $100. Features that impact price include insulation/R-value, weight and size, and added features such as plush tops or integrated pumps.
When purchasing an inflatable mattress, be sure that you have the means to pump it up. If you can't blow it up manually, find a small hand/foot pump or automatic pump. Also, to fix the mat on the fly, you should purchase a puncture repair kit.