You can make a smoothie with any blender, but for proper digestion and the best benefit, the ingredients need to be blended thoroughly.  Many blenders will give you “chunkies” to drink instead of smoothies, so I like a high-speed blender like Blendtec or Vitamix.  I have a lot to say about the best blenders for making your green smoothies, but you can get a pretty good result with a cheaper blender if you don’t use frozen fruits or veggies and make sure to blend in ingredients a bit at a time. Make sure the mixture is a smooth puree before adding in the next ingredient. Add a bit more water if you feel the smoothie is too thick. I even have a reader who makes all her smoothies with her hand-held stick blender! It’s great for making smoothies on the road, at work, and even at home.