As for fire pans, an aluminum baking pan (like for cooking a turkey) *might* meet the letter of the regulations, but in practice, aluminum is just not tolerant of the temps generated once the camp fire burns down to coals.
The cheapest thing I can think of is a wok from a thrift store for $5. Or a wok from Walmart for $5 (for their 13.75″ model) to $20. It will last forever, is readily available, and is fairly multipurpose. You can haul water in it, use it as a uplands basin for washing hair or taking a sponge bath, digging holes in soft sand and even as, *gasp*, a wok.
I’ll repeat my suggestion from other threads for a charcoal starter as a fire place on rafting / boating / car camping trips.

About $12 at Home Depot or Walmart, anything you burn will burn MUCH cleaner and with less smoke in such a chimney with great draft than in a traditional campfire. A few Ti tent pegs over the top allow you to place a pot of water, asparagus spears (done that) or some bear meat (done that, too) to roast , but be prepared for it to cook REALLY fast unless you’ve let it burn down to coals first. Such a charcoal lighter, placed on a small steel wok or piece of Ti foil would be better, in every way (less smoke, fewer sparks, better heat output) than any open campfire. 3 and 4 of us have gathered around one in our folding chairs. That’s about the limit and for a larger group, a more open fire (with all of its drawbacks) would allow more people around it.