Some are more suitable than others for sautéing; some are best for salad dressings. The first thing to consider is heat. If the oil is high in saturated fat, it can be heated with less damage to its structure than those lower in saturated fat. Get to know labels. The best oils for sautéing are peanut oil, high oleic sunflower oil, high oleic safflower oil, sesame oil, and for medium-heat cooking, olive oil (although don't waste your expensive extra-virgin olive oil on the sauté pan, reserve that for dressings.)
Walnut oil, grapeseed oil, pumpkin seed oil, avocado oil and almond oil all are best used in dressings, or other no-heat applications. When baking, most recipes call for "vegetable oil" which is a generic term that usually means the manufacturer has used the cheapest means possible to fill up the bottle. In cases where "vegetable oil" is called for, used Canola oil. It is low in saturated fat, so it is more heart-health friendly than other oils.
As for purchasing, it's best to buy organic oils if possible because most of the plants oils come from are routinely sprayed with pesticides, unless organic.
As for storing, if buying large quantities, make sure it is in an opaque bottle so that light does not penetrate, which can oxidize the fatty acids, making the oil go rancid and lose its beneficial properties. Keep lids tight to minimize contact with air. Oils should be stored in a cool, dry place: on the ledge above your stove is the absolute worst place. Unrefined oils, with the exception of olive oil, are best stored in the refrigerator.