A ton of different blender models are available and it can be a challenge to determine which one is right for your needs and budget. Many reputable companies make blenders including Bosch, Oster and GE. Many people believe it's a good strategy to buy a quality blender from a brand that you have grown to trust over the years. A cheap blender from Walmart may work for a year or so before it dies or needs expensive replacement parts.
The main ways that blenders differ are their power, what they are made of, and the features they have. A more powerful blender will always be more useful since a less powerful blender may have trouble crushing ice for smoothies and icy cocktails. A metal blender may look better, but might require a bit more cleaning than a plastic model. Blender jars typically come in glass and plastic. A glass jar is usually more attractive and easier to clean, but can be fairly easy to break if dropped. A plastic jar tends to be hardier and won't be as easy to crack or break. If you anticipate using your blender for tough tasks every day, you may want to consider an industrial or commercial model instead.
It may also be helpful to read reviews online and ask your friends which blenders they have and whether they like them. Buying a blender is a very personal choice and if you spend the time to understand your options and needs, you should be able to buy a blender that makes you happy for the long-term.