Gzus christ noob do some research and figure it out for yourself.
2 people can buy the same exact package of links and have 2 completely different results because 1 person KNOWS how to use those links and the other person doesn't.
Furthermore, It's smarter to think in terms of "where can I buy good, high quality real estate" rather than "where can I buy links".
If you wanna be in any industry or niche for the long run, you should build your own PBN. And ftr I don't get a penny from the banner in my sig. I promote it cause I have nothing of my own to promote and think it's a good service.
If you wanna just rank and bank, which is becoming harder and harder to do these days, then you can get sloppy, create buffers and go crazy buying up links from random link sellers. There was a case study done not too long ago where a guy... I think his name was "lover" or something provided really good results.
Then there is parasite SEO where you just spam authority platforms to oblivion. And some of those properties can rank for years if you do it right.
The goal is to make money right? So do some research and try to stop asking questions that have been asked 10,000's already.