Good info so far!
Want to add .... I THINK (better ask to be sure) that Rivanna changed their match this month to the forth Saturday (AFAIK, it was because of a north carolina match that a lot of the regulars/staff were planning to attend). So check before you go.
There is a certain amount of gear that you'll need.
Bare minimum:
pistol/revolver 9mm minimum
3 mags/4 speed loaders
holster has to "retain" the pistol and cover the trigger guard
mag pouches/speed loader carriers (could be your pockets, but you'll really want pouches ASAP)
eye protection
ear protection
willingness to help out - this will start with taping targets after a shooter is finished and could should grow into helping set up stages, teardown the match after it's done and maybe become trained as a safety officer.
2x the amount of ammo you think you need, or more (maybe someone else will be short ...)
garment to conceal your "heater" Can be an untucked shirt, lots of folks use a vest. If it is hot enough the match director may ease this requirement. But last weekend in the 95+ heat and humidity the match
natzi director did not
If you are missing any of the above and you have a "common" gun type there's a good chance their might be a loaner around. Last match I saw couple of glock mags lent out, and a cover vest. And I sold someone a couple of boxes of ammo. As you are traveling I wouldn't leave it up to fate. Buy it, or check ahead just to be sure.
Other niceties:
bug spray
sunscreen
hat
cooler/beverage
chair
lube/CLP
gun cleaning stuff
basic tools
More mags - this will keep you from rushing between stages to get your mags loaded for the next string.
Mag loaders/thumb savers ... you'll stop using these after a few matches as you find loading mags isn't really that bad.
parts kit for your heater's most weakest links
New grips
skateboard tape
Gunsmith work on your gat (cuz it will seem a lot easier to pay your way to the top than to practice :) )pencils or pens
Membership card (first match is usually not required). Membership supports our sport.
Lots of this stuff can stay in your car, but can be nice to have just in case.
Eventual upgrades:
New holster - doesn't matter which you have, you'll see something else you like better ...
New pistol - this usually happens just after you spring for new holsters :)
Electronic ear muffs - these are nice as they allow you to hear so much better!
New glasses - eventually you'll put your work safety goggles back in the tool box and get a set of unscratched lenses on your nose .... OH, that's what the target looks like.
New Glasses - then you'll see that yellow/rainbow/reflective lenses look sooo coool.
Video camera - you can pick up things to work on in your game.
Range bags - at first you'll think of all the things you need and buy a 15 cubic foot model. Then you'll realize that you really only need a box of bullets as you come to the match packing and with your eyes and ears perched on top of your head. So you'll get a minimal bag. Then you'll settle on a bag somewhere in between.
Timer - makes all of the difference in the world in how you practice. Dry AND live fire.
Reloading gear ... to get that perfect load that doesn't recoil
brass bag, to get your reloading hobby started with spent range brass. You'll toss this when you figure you'd like to know the history of the brass that you are loading, and when it becomes worth it not to pick up brass and just buy once fired brass online.
copy of the rulebook for reference
Tactical pants/shorts - to match your vest
Underarmor shirt - Cool on several fronts
Tactical shoes
Tactical shoelaces
Tactical socks
Tactical underwear
Sooooo, there is lots of serioius stuff mixed in with some tongue in cheek. I've lived thru some of this advice, watched others go thru some of the others, and had a bit of fun making up the rest.
Also for your gear. Folks will let a newbie slide, so use what you have, but be careful when you buy that it is legal in the sport. If in doubt, ask before you buy, or consult the IDPA rulebook. (newly updated this year).
Lastly, if you think the list above is bad, multiply it times 3 if you decide that you want to get into 3 gun matches but also multiply the fun factor as well.
Ok folks .. what did I forget?