I'm too late to be any help to you but I was recently in there and was quite disappointed. It was fabulous a few years ago, but from what I could see it was full of stuff you can now buy in the uk anyway, and for less money! I ended up with a few Sephora own-brand items and some Korean face masks because I couldn't bear to leave with nothing. Did you find anything in the end?
As for price the only real bargains I find are at outlet malls when they are having an extra special discount or the occasional great find in Marshalls. Buy something as a keepsake or because you love it only. As for products the world is so universal now - it is rare to get only US specific stuff.
I think their own brand make up is lovely. The gloss that's like a lipstick is great. I also like their mascara that's in a tube that looks like it's quilted and the small pots of nail varnish. I have one of their own perfumes in Orange Blossom and vanilla too which is gorgeous.
The Sephora favorites boxes - lipsticks etc (change every so often) are great value and have different brands which are mini and full size. Bite beauty lipsticks are great too and not available in the uk. Go for the value sets or Sephora exclusives
The foundations and concealers have a much wider range of colours than you will find in Europe, even in European brands. (I personally hate the Americanism ‘people of color’ because *everyone is a colour, numpties*)
Don't know where you live op but there's one at either angel tube or Islington. Can't quite remember. It was a one hit wonder for me. Like body shop but not iyswim. I used body shop from a teenager til a couple of years ago. The branding doesn't work for me any more.
We were in NY last month and Dd(20) was so disappointed with Sephora, yes, they had beautiful products, but no cheaper than in the UK. (QVC sell Tarte, and you can try for 30 days and return if you don’t like it)