Are the Sephora Collection products actually just as good as the really expensive brands or is it like a trap for people who dont know better?

I have a wedding to go to in like two weeks in Austin and it is gonna be so hot and I realized I have basically zero makeup that actually stays on my face. Honestly I dont know anything about this stuff and I feel kinda stupid even asking but im looking at the website and some of these foundations are like 50 or 60 bucks which is way over what I can spend right now. My total budget is maybe 100 dollars for everything which I know is probably nothing in the makeup world lol but thats all I got.

I saw the house brand stuff is way cheaper like half the price of the fancy names like Charlotte Tilbury or whatever. I really need a foundation and maybe a mascara that wont run when I sweat at this outdoor reception. Is it just cheap because it sucks or are you just paying for the name on the fancy ones? I dont want to waste my money and look like a mess for the photos. Sorry if this is a super basic question I just dont want to break out or have it melt off my face in ten minutes... please let me know if those cheaper ones are okay...