Sonia Kashuk Blending SpongeThe Sonia Kashuk Blending Sponge ($9.99, Target) is a reusable sponge that is used to apply and blend your foundation. It has a precision tip, making it easy to reach small areas (such as under the eyes, around the nose, etc.)
Since I don't own the original Beauty Blender ($19.99), I won't be able to compare them, but I've read several reviews and have seen many recommendations for the Sonia Kashuk Blending Sponge as a good dupe for the Beauty Blender.
I've never used a reusable sponge to apply my foundation, but I watched a video by MakeupByTiffanyD and found it extremely helpful. In her video she shows how to use the Beauty Blender and does an overall review.
You are suppose to run the sponge under water, then squeeze the excess water out. By doing this, it won't soak up as much liquid product, and the sponge will feel softer to the touch. Then, dip the bottom sponge in your foundation, and apply it in a stippling motion or a dab-and-roll motion. For concealer and smaller areas, the tip of the sponge is helpful.
I followed the directions and stippled my foundation on with the sponge, and right away noticed that I had to go back a couple of times for more foundation, which I never typically have to do. It seemed to eat up more foundation than a brush would. Not only did the sponge "eat" up more foundation, but my foundation also looked sheerer than usual. It applied my makeup very thin on my face, and I could still see redness from my cheeks peek through, which would never happen when applying with my foundation brush.
My foundation looked very even, and there weren't any areas with caking. Sometimes when I use my brush, too much foundation will sit in some of my fine lines - especially my laugh lines, but with the blending sponge it applies the makeup very thin, so it doesn't happen.
Lastly, one thing that bothered me was the actual smell of the sponge. It reeked of fresh rubber. The smell actually gave me a headache and made my hands smell like rubber. I've washed it quite a few times, but the smell is still a little bit present. I'm sure with regular washing it will go away, but I thought it was worth a mention.
Overall, I'm not completely sold on this sponge and I don't think it's really worth the hype in terms of foundation application. I think this sponge would work much better with cream foundations, as it seems to absorb too much liquid with my regular foundation. Also, because it seems to sheer out my foundation by applying it in a very thin layer, it'd be ideal for opaque and heavy foundations.
I'll only be using this sponge for blending and touch-ups when I need it, and I'll be sticking with my brush for application.
Please bear in mind that this is my opinion only, based on my experience! :)