I was just about to ask a similar question... So kudos for that. After seeing the answers we just bought another car pass (we have 4 people (2 cars now).
We got this tent on Amazon during the deal of the day for like $80, but it's big:
Coleman Red Canyon 8 Person Tent, Black https://www.amazon.com/dp/B00J955G10/ref=cm_sw_r_cp_awd_dBWFwbBBW9QJR
We will also have a 10x10 or 12x12 shade tent.
With two cars, I'm hoping that space will be left over for our pop up shitter/shower too.
If I were you I'd just go pick up an 8 man Coleman tent from a Walmart something like
I know that there are better tents out there but for the price point you really can't beat them. I like these cheaper tents (I have a 4 man and a 10 man) because yes they are heavier but when your 5 year old stabs a stick he found from the woods through the side, you don't want to have a stroke.
I would avoid at all cost gimmick tents. Ez up tents and inflatable tents are just really trying to entice people would want something that's cool the first time but once the pole bends and you have to throw that $300 ez up tent away it stings.
Plus you can set it up in the back yard and they can run in out out of it track in all kinds or dirt and mud and you still don't have to worry as much as you would with a $500 tent.