Does the 30 dollar cost cover both sides of the phone screen replacement?

noahfromgreenwood wrote:

I have an 8 plus and both sides are cracked from the fall

Then it would be subject to the out of warranty replacement cost. In the United States, that's $399 plus tax, or $99 plus tax if you have AppleCare+.

iPhone Repair - Official Apple Support

Model	With AppleCare+	Out-of-warranty
iPhone X	$99	$549
iPhone 8 Plus	$99	$399
iPhone 8, iPhone 7 Plus	$99	$349
iPhone 7	$99	$319
iPhone 6s Plus, iPhone 6 Plus	$99	$329
iPhone 6s, iPhone 6	$99	$299
iPhone SE	$99	$269

What 30 dollar cost? At least if you're talking US dollars, the only thing that comes close is the AppleCare+ screen replacement, which allows two instances of repair at that price. That would only cover the display and not a glass case like on an iPhone 8/8+/X. That would be covered by the other accidental damage, which is $99.

The out of warranty repair prices are way more than that for just the glass/display assembly.

It certainly wouldn't be under the current battery promotion.