Can anyone advise how good the onsite-camping store is, and is it more expensive than normal stores.

I am coming from the UK with a mate and we want two tents but really don't want to drag them all the way to america. We are off to Las Vegas then San Francisco after the festival so didn't want to lug them on and off planes and have to pay extra baggage allowance. My plan is to buy a tent on-site then just leave it behind. Same for sleeping mats