Both
better and
worse than the usual kind of
bookstore. Online bookstores have
every in-print book
in stock, along with many that aren't in print anymore.
CDs,
videos, and
DVDs are often stocked by the larger ones as well. They generally offer
discounts on each and every item they sell, which helps offset the cost of
shipping it to you -- as long as you're ordering at least three items at once, the final cost is almost always
in your favor.
In addition, there are the fringe benefits of having the store be on the World Wide Web. The more sophisticated online bookstores allow visitors to post reviews of books so that future prospective buyers will know if it's worth getting or not. They link to other books, music and movies you may enjoy based on previous buyers' interests. And, of course, they're open 24/7.
Of course, there are downsides. You can't go in and just flip through a book to see what it's like, except in the rare cases where an excerpt is provided online. You can't really browse a browser-based catalog the way you can a full shelf. There's no cafe to sit and snack while you're enjoying your new purchases. You have to wait a few days for your shipment to arrive at your doorstep. And the magazine section is pretty much nonexistant.
But as long as you're primarily motivated by economics, and you're not in too much of a hurry, online bookstores are generally the way to go. The only thing better, in my opinion, would be treasure hunting in a good used bookstore.