Hi!

Welcome!
I think you'll be very happy with your decision to get a Yorkie. The love, affection and companionship they give is unequal...in my humble opinion.
Congrats on your impending freedom from school and journey into 'the real world'

Do you have a job yet? Will you be moving to a new location? I would wait until I was settled into wherever you will be moving to after graduation. One less move for the Yorkie to have to deal with.
As cute and adorable as puppies are...perhaps look into a slightly older dog would fit your situation better right now. There is a great board here, Yorkies For Sale or Wanted & Yorkie Rescues & New Homes Needed. Trust me when I say that they will bond as good as any puppy. We got both Annie and Boo when they were 5 yrs old and both of them are stuck to us tighter then either of the 2 puppies we have now. Just a thought...something else to look into.
Instead of a crate, I like the exercise pens. They can conform to any shape or area. It allows more room for the dog while still keeping them safely confined. Yogi does great in his. One area has his wee-wee pad, food, water and pillow in another and some room for him to walk around and play with his toys. Price is similar but I feel there's more versatility with the pens over the crates.
Medical expenses will vary greatly depending on were you live. Call around to some of the vet offices - even drop in for a visit - and get their standard price quotes. I think I paid around $300 for Gracies spay. There's also shots and worming to consider. Again, with many mature dogs much of this expense was incurred by the original owner, so that's another plus.
There are several good breeders on this site. You can also research breeders via the AKC. You should get a lot of good advise here on what to ask and what to watch out for. Perhaps post in the Breeder board too, they should be able to give you a lot of good info.
Congrats again, and please post pictures after you've found your new best friend!!!