This is an old dirt lot with several sites for overnight RV parking, which the gift shop allows for free for a night as long as you are self-contained. No tent camping or sleeping in your car allowed (because there are no restrooms available). 

Each spot has a picnic table and a few have a shade structure as well.

The other side of the street has more sites available for $15/night and they include power hookups. No other amenities available here. 

These lots are just outside the Petrified Forest NP south entrance and it’s so convenient to stay here if you’re going to be visiting the park. We stopped at the gift shop to make sure we were good to park here for the night and also to make an obligatory “thank you” purchase. They have lots of jewelry, petrified wood pieces (ranging from cheap to crazy expensive for the large polished pieces), clothing, gifts, stickers, etc. They also sell beer for $3/can but all they have is Budweiser. 

Good-ish cell reception here. AT&T had 3G, Verizon had LTE, and T-Mobile was roaming as always.