Spongeify!

The Miracle Complexion Sponge from Real Techniques is an orange, blender sponge with a tip on one side for blending out and over blemishes, a flat side for using around your nose and eyes, and the traditional rounded side to bounce around large areas of your face to blend. It retails for $5.99 and I have to say...I like it better than my Beauty Blender.
The price point is a huge factor, compared to the $19.99 the Beauty Blender retails for, but it also does, I think, just as good of a job at blending my foundation and giving me the ability to keep it as sheer or full coverage as I need for that day.

I run it under water, squeeze out the excess so its just damp and then use it to put on my foundation, which I dot all over my face.
Every 3rd use or so I'll actually wash it rather than just rinsing it out. I use Dr. Bronner's Magic Soap-just a few drops, mash it around a bit, run it under the water, mash it a bit more, and then rinse until the water runs clear.
When I washed it for the first time I noticed that the sponge doesn't actually hold on to much of the product so I know that I'm not wasting a lot of my foundation because its sitting in the sponge.

I know there are many, many dupes out there for the Beauty Blender and most of them I would say "don't waste your money" no matter how affordable it is. But Real Technique's Miracle Complexion Sponge is one that I say "go for!" because it is a real dupe for the Beauty Blender.