Funny that you posted this OP, I was actually thinking about this very question when I looked at M School costs and initially thought they were outrageous, but then considered all of the ancillary costs of an HPDE. IMHO M School is still very pricey, but not outrageously so.
As a novice running stock equipment I think your wear rates will be low enough to almost be negligible. People who go through whole sets of tires and brake pads in a weekend or two are typically running Extreme Performance summer tires (treadwear ratings of 80-120 compared to 220-300 for Michelins) or R-compounds as well as dedicated track pads, neither of which you should be using as a novice (in fact R-compounds are typically banned until you're advanced). I'm in the Blue group (one above novice) and was recently promoted to Yellow but haven't run with them yet, so here's my experience:
Tires: I consider tire wear somewhat negligible. I had to swap my PS2s for PSSes early (long story), but I had 6 track days on them in addition to DDing my car and driving it harder on these Texas back country roads out, and measuring the treadwear when they were removed, I would have gotten about 16K out of my fronts and 14K out of my rears. If you take a look at threads around here, that's a tad early for fronts (which do wear more on track days), but about average for rears. People who really baby their cars have apparently gotten 30K out of their fronts, but who wants to do that?
Brakes: I had 6 track days on my stock pads and had PLENTY of pad life left when I upgraded to better pads because of pad fade and the fact that my last track day messed up my rotors (warping or uneven pad deposits, either way it didn't fix itself after 4 weeks; BMW replaced pads and rotors for free though
). That said, the track I ran most is known to be pretty light on brakes, so that can vary dramatically from track to track. Also, as others have said, definitely flush your brake fluid before you go, and ideally upgrade to something like ATE Type 200 or Super Blue because even a novice on a track that's easy on brakes can get a spongy pedal with the stock fluid. Those two fluids I mentioned are identical except for color and only cost $15/bottle.
Inspection: Usually free, but shouldn't be more than $20; no idea why the person above said $150.
Insurance: Depends on the value of the car. I know Lockton is popular for that, and their rate for a full weekend event is the same as a 1-day event. For me, my regular insurance carrier (Amica) actually covers me on the track as long as I'm not practicing or participating in a race, which is a HUGE plus for me, but I know that's not true for most carriers, and in fact I think for some carriers their coverage of HPDEs varies from state to state.
Hotel: Just stay at a cheapy Motel 6 or something. You'll be on the track most of the day and then want to grab food, but honestly after that you'll be so tired you'll just need to collapse into bed, only to get up bright and early the next morning. Even though I usually go to bed around 11, after a track day I'm usually asleep by about 8:30, so you won't really have time to enjoy a really nice hotel IMHO. And seriously man, get LOTS of sleep before a track day and don't go out drinking the night before. You have no idea how hard driving on the track is on your system and how much faster you can be when well rested.
Gas: I burn just over 3/4 of a tank each day on the track. Plus gas to and from the event.