mattress in a pack and play ?

Bee • FTM 💜 blessed 💜 SAHM Mother to a beautiful baby girl who is the light of my life

so my baby grew out of the bassinet fast and we are room sharing with the pack and play. it came with a thin foldable mattress pad, but I noticed they sell 3" mattresses for pack and plays. what do you momma's use when your baby sleeps in a pack and play ???