How long before PBN links work?

I wouldn't expect any movement from a handful 12$ Links... I mean, I wouldn't even buy cheap links like that. Just build your own PBN, it will give you more control over your links and you can even get them faster indexed if you need to.

It's hard to gauge but once you find good providers, best to stick with them.
I bought 10 links @$30 each 3 months back from a provider who sent me screenshots of clients ranking improvements and they were amazing, so I ordered.
My main keyword for these was at 36, on 28k searches and I thought this would get it to the first page hopefully.
Sadly the keyword dropped by 60+ places on that keyword but also on 7 others.

I had the links removed and the rankings are very slowly naturally coming back.

Not all PBNs are made the same !

it depends on this niche...if it is high competitive then it will be difficult.

Yes its strange how supposedly good pbn links can make rankings go down. Expensive links as well.

I tried renting some links off a buyer that doesn't advertise here. He's one of the big names in seo and his links pushed a 74000 keyword down from approx 10 pos to 22 pos.