So I've had this brush for about a year and it's my absolute favorite brush to use for liquid foundation or even powder products. I own the MAC 187 and I must say that although it works pretty well, I prefer the ELF brush because the bristles are a little bit more denser and so very soft! It feels amazing on your face. I've even used it to apply blush and bronzer when I'm in a rush and can't put my hands on my other brushes quickly enough. That makes it one of if not THE most versatile brush that I own. And the cost??? If you're in the US it's just $3.00 and if you're in the UK it's 3.50GBP.
As far as I know you can get them in some stores in the US, but in the UK you can only access it via the ELF UK website. Have no fear though! These guys (the UK store) have the best customer service ever!!!!!! Let me know if you get your hands on it, or if you already own one.