I have never once purchased expensive "beauty" products. I believe they're about 99 percent marketing. The best hair-care product I have ever used is plain old jojoba oil, which I use to keep my wiry gray hair a little bit manageable. I apply quite a bit to my ends and everything below my chin after each shampoo.
I buy my makeup from Target or Walgreens. If it's expensive, I won't even consider it.
I used to slather Vaseline on my face as a teen because I believed it would keep me from getting wrinkles later! That was kind of dumb, but at least it was cheap!