A pit pass is the paid, per-person credential that admits a driver or crew member to a racetrack's restricted pit area. Everyone going through the pit gate buys one, and it comes with a liability release you sign.
Price and terms are set track by track, so look yours up. High Limit Racing’s FAQ is blunt about it: “The pit pass price is the same for adults and children at each event. Pit pass prices may vary, so please check the ticket page or track’s website.” The biggest variation is what the pass includes — at Eldora, “a pit pass also allows for admission into the grandstand area and General Admission seating areas,” which is not universal; check yours. Age minimums vary too: Eldora admits “only persons 14 years of age or older” to the pits, and 14-to-17-year-olds need a parental consent and release, notarized unless signed before an official. Sanction paperwork is separate again — IMCA requires its own minor release before a membership is processed.
Pit passes are charged per person per event, so a four-person crew multiplies a small number by every night you race.