There are so many choices when it comes to drugstore foundation. As it usually goes with makeup products, some are bad, some are good and rare ones are really good. 
But, what if you don't have time or nerves to try all of them and you want just one foundation that will work? In that case I suggest buying Revlon Colorstay foundation. It works like magic, when my face is broken out and reddish one layer of this foundation is enough to transform it into flawless perfection. 
I don't use it everyday, because I don't wear liquid foundation on daily basis, but when I'm going out it's a must. The name is appropriate, when you apply this foundation it will stay on no matter what and I mean it. Also, it will look like when you applied it all day long, no cakey or oily looking face. 
It might even be hard to remove it when you are taking your makeup off, so make sure to cleanse well. There are two versions of this foundation, one for normal/dry and the other for combination/oily skin. It also has SPF 6. 
The best way to apply it is with synthetic foundation brush, although you can use makeup sponges or fingers as well.