You don't need a special refrigerator or cellar to store wine that you want to age, or just don't want to drink right away. Any cool, dark place, such as a closet or pantry, will do. Keeping the wine out of the sunlight and at a consistent temperature is key. You should also invest in a wine rack - when the bottles lay flat, it keeps the cork wet so air can't get in through cracks and promote spoiling. Wine bottles with screw tops don't need to lay flat.
Once a bottle of wine has been opened, you want to limit the amount of air exposure. Re-corking and refrigerating a bottle of wine shortly after opening it will keep it fresh for up to 2 days.
A vacuum pump wine sealer (shown above) is relatively cheap and can keep wine drinkable for up to a week. They run around $10, and it includes a pump and a couple of stoppers.
Hopefully this little handy post will keep you from drinking a glass of vinegar or tossing a half-full bottle of perfectly good wine. Cheers!