There are zero products I've not been able to find great versions of in the affordable drugstore brands. It's all about knowing which brand does which items well. It's much more fun for me to find great items at an affordable price than it would be to spend loads on one single item from a beauty counter that still might not be that good. It's a bigger risk.
For liquid eyeliner I've never found anything better than Rimmel Glam Eyes. I read a review by sali Hughes that said it outperforms even Chanel, Dior, Bobbi brown versions.
Loads of people swear by Rimmel's face powder, I've been using it a decade and everything else I've tried pales in comparison. Even the urban decay de slick powder which is five times the price or more.
I love urban decay eyeshadow but sleek's are comparable. So buttery and pigmented and blendable.
Soap and glory and rimmel's Kate moss line do brilliant lipsticks.
Rimmel's eyebrow pencils are brilliant and £3
As others have mentioned, revlon and rimmel do brilliant foundation
Sleek blusher is amazing and they have a perfect dupe for NARS orgasm
No difference in expensive and cheap lip balm at all.
Barry m do great liquid lips!
Collection concealer has a cult like following, loads of people say it's as good as tarte shape tape and urban decay naked concealer
Soap and glory eye pencils have great pay off on the waterline and last all day
And L'Oréal paradise lash mascara is amazing, I prefer it to benefit bad gal
Honestly there's no need to spend more than a fiver on most products to get something brilliant. Just do your research and read a range of blogs and reviews. I have been burned by buying an expensive counter product that's been shit (the UD heavy metal glitter eyeliners for example are thin watery and smudgy and barely show any glitter up, whereas the collection glitter liquid liners are AMAAAAAZING in every way). It's not worth the risk cos if you get a duff for £30 you can't return it, better to get a duff for £3!
For high end you're paying for a brand, weighted packaging, a full time staff member, the illusion of luxury, adverts in magazines. It's just not worth it. The stuff inside isn't necessarily better and it's usually people being sucked into the glamour of it that will claim it's always better.
I do splurge on UD eyeshadow palettes as I use them daily and get loads of wear from them and love the shades and design. But other than that I'm such a drugstore girl.