I got some great advice from a new friend (I am going to my first crop next weekend) she said to bring a commuter type cup with a lid that wont spill!! Chances are you are going to be thirsty and if you spill you drink on your layout or someone elses it could spell a huge disaster!!
Cant wait to hear about your first experience...make sure you let us know how it went. I will be sharing mine next sunday!! Have fun...and I agree make sure you leave room for purchases!!