Oh, I deworm every 8 weeks generally. Making sure to cover tapeworms at least once a year is probably a good idea, and there are different times of year to target different parasites (like fall for bots, etc).
Vaccinations depends on what area she's in and what she feels is necessary. I usually do West Nile even though we don't have a ton of cases here but I have never vaccinated for rabies.

First aid depends on if she's boarding or not - I always kept a pretty wide variety of wound sprays/furazone/etc, plus syringes, needles, bute, banamine, vet wrap, etc. etc., on hand, until now. I still have some stuff left over, but now that I board I a) don't really have enough space at the barn for my first aid stuff, and b) don't really have a need since there is a shelf stocked with first aid supplies. (It's still a little strange to me, since I'm used to being pretty self sufficient where my horse is concerned).

I'll second Analise - I love auctions and I've gotten some spectacular deals. Same for Horseloverz.com, and you can also check eBay for some tack items. I bought my Thorowgood saddle off there. My area has little in the way of English tack, so I usually have to look online unless I want to spend an arm and a leg.

I've found you can just start out with the basics and gradually build on that. A lot depends on whether she's boarding or not, and if she is, what they provide. I don't really need buckets for my own horse, but I already had them, so I happily hauled them to the barn and left them there. Don't forget to check out nonhorsey places, like the dollar store, for items. I bought 5 gallon buckets and lids for hauling water (I used them when I hauled out to trails, etc, to bring water along) at Ace hardware - much cheaper than horse buckets, and since I wasn't using them for my horse to stick his fat head in (I have an actual horsey bucket for that) it works well.

Spooksandbolts wrote:

How terribly sad for you that the extensive advice you've been given wasn't what you wanted and wasn't sufficient for you to figure what to do. 
Luckyduckerpart2 wrote:
Sometimes I wonder if there is an asshat of the year award you may be competing for that we don't know about.