The materials that are most commonly used in prosumer 3D printing are PLA and ABS in reel form. Other materials include epoxy resin, glass polyamide, wax and even metals such as steel, silver and titanium.
ABS is familiar to most of us as the material used for Lego brand toys. It's light, durable, and strong. It's a little more demanding to use than PLA, and also gives off an odor of melted plastic during the build process. ABS tends to curl upwards as it cools so a heated printer bed is needed to keep it warm during printing. But ABS is ideal for utensils, tools, and items which will require some degree of flexibility or be exposed to higher temperatures. An ABS printed object can also be easily reworked by sanding, drilling, or finishing the object with acetone.
PLA is derived from corn starch and other renewable ingredients, and is fully biodegradable and non-toxic. It becomes printable at lower temperatures, so it is easier to print safely. However, that thermal sensitivity is not ideal for designs that will be exposed to high heat. A PLA printed object tends to be much harder and more brittle than an ABS object, which means that it cannot be reworked after printing, as well as having a tendency to crack in higher-stress environments. Summarily, PLA is a more ecologically friendly and forgiving material, while also being odor-free, although not quite as strong or durable as ABS. We recommend PLA for your daily printing, and ABS for more demanding jobs.