Is there any effects a $30 iPhone 6s Plus screen can cause?

I just dropped my iPhone and I don't really want to send it to Apple for $169. I was wondering if ordering an off brand (amazon) iPhone 6s Plus screen and letting someone who knows how to replace it to replace it. But since it's off brand, will it affect other things in my phone or will it just be more vulnerable to break?

Impossible to know for sure. If you have a large mall in your area go there to one of the phone kiosks first and see what they say. Get some professional advice before you make a decision. Unfortunately, this site is not always a good place for professional advice, so take your phone somewhere you trust for an opinion.

Since you dropped your phone you could have damaged more than just the screen. So you take a big chance buying some brand x screen, taking the phone apart and then hoping nothing got damaged in the fall or during the replacement. Go with the apple fix if you plan to keep the phone for a while.

Quit social media.