There's nothing like a cool, frosty drink at a summer party, but once your guest list starts to grow, making dozens of frozen drinks in a regular blender and keeping them flowing can be a real hassle. Plus, let's face it -- how can you be a great host if you're stuck by the blender all night? Fortunately, there are many different margarita machines for sale or rent; you just have to know what to look for so that you choose the right machine for your needs and budget.