Lip clip ?
 

To install an ITR lip on my 00' Integra, do I need a clip? It's supposed to be some sort of clip that attaches to the car, AND THEN the actual lip goes on. True, false?

BTW it's not an aftermarket lip, it's OEM.

false. just use zip ties to hold it on from underneath. on the sides, use self tapping screws.

true.

if you want to install it correctly and not have it fall off because you ghetto fabed it, you'll need to get the metal speedclips and bolts from acura or honda that slide into slots under the bumper and have threaded holes that allow you to bolt the lip to.

Approximately how much do these cost?

The clips and bolts were something like 30 dollars I think when I got mine - there's 7 of them, I believe. You can use the stock screw for the sides that's already on the bumper.