There's enough great balsamic out there to meet every budget so theres no need to blow a mortgage payment just to wet your whistle. The simplest thing to do is to find a bottle with an easy price tag that has "di Modena" somewhere on the label and your good to go. There is no reason toy can't use it just like any other vinegar. Go ahead and mix it up with olive oil and throw it on your salad.
Like pipe tobacco, balsamic changes dramatically when aged. It can be bright and sharp when fresh, but with age it becomes very rich, sweet and syrupy. The fresh stuff is great for salads while the aged balsamic often finds broader use. In Italy, we use it to add sweet and sour to all sorts of foods from fruit, to gelato to liquor....it goes well with just about anything. Try a few drops on a strawberry, or sprinkle a bit more on vanilla ice cream. One thing to keep in mind though, in America Italian food is often over the top with spices, garlic, spicy peppers, etc...in Italy things tend toward restraint, so go slow when seasoning.