For 5+ years I was an event vendor, and this is a list of things that were sorely missed, over the years. Vending at all day events is almost like camping. Best be sure you have it ALL - no one ever wants to run to the store, once you are set-up and the event is closed to traffic.

Office supplies/Swag
Tool Box w/extention cords
Staff Beverages/Water
Change of Clothing
First Aid Kit
Wet wipes, the porta johns get nasty after 10AM
Starting bank that is heavy on singles and fives, double what you think you need, if your event falls on a gov't pay week.

As a seasoned vendor, I could work my space with only 2. However, if I was working your LA event, 4 would be my minimum. Each staff member were given their own starting bank, with monies collected down to the bank -several times a day. Be aware that passing bad bills is common at a large events.

What swag you choose really depends on your budget. My crap is all laser etched and range from 25 to 70 cents each. I'd be happy to share my supplier information, he's good to work with, and hasn't been too shocked by my designs. Now I think he's more amused. but has declined my offer for a link back.

Oh, and be sure you really read the vendor's contract. It's very simple to miss a detail that can sometimes cause your merchendise to get pulled. I will not bore you with The Tale of the 4 gross of Silly String.

Most of all .. have FUN! It was a sad day in Arcaia, OK when the 106 degree temp and 16 hour days, forced me to close that fun chapter of my life.