Amarone (i.e., true Amarone) is inherently expensive to produce. It is also sought after, which drives up the price as well.
It is made by taking the ripe grapes, and allowing them to air dry for a period of time. This concentrates the juice, making the wine more full-bodied, intensely flavored, and higher in alcohol. This process, called
appassimento, takes time and money, of course.
As to laying your hands on a reasonably priced bottle, I have two suggestions. One is a visit to a Trader Joe's, if you have any nearby. They often have an Amarone in the twenty-something dollar range.
Another suggestion is to try a Valpolicella Ripasso. This wine is made by "repassing" a normal Volpolicella through the leftover Amarone skins.
Ripasso wines are sometimes described as a "baby Amarone." Here is a site to this effect:
http://www.winewordswisdom.com/wine_reviews/ripasso-wines.html