First thing you need to buy is a lead/collar, don't buy the muzzle until you get the dog as you don't know what size muzzle the dog will need. (otherwise, buy all sizes if you want).
Toenail clippers a must (I see so many trainers who forget that the feet are the IMPORTANT part of the dog), grooming brush also handy (soft bristled brush for the short haired dogs). Stock the shelf with first aid things such as pump spray debrisol/cetrigen, Healagen cream, peroxide, metho, tea tree oil, etc etc.

If you have a race dog you will also need to have liniments (rapidgel, penetrene etc whatever suits you to use) if you can't afford an ultrasonic machine or lazer.
Put some money aside for muscle men to check the dog each week or after each run. People think it's easy to check the dogs themselves and proclaim themselves to be an expert but actually they can only do the basic checking properly if that.
Some have the 'knack' of knowing where the dog is sore though, just by keen observation and careful attention to the dog's overall attitude/gait/muscle tone.

Oh and you will need a feed bowl, water bowl. A teaser is the last thing you really need for the racedog as it's unimportant unless you have a young puppy you want to start out teaching it to 'chase'.
Too much teasing with the teaser toy actually can be counter productive for the racedog.

Um that's about all I can think of that you need lol there's heaps more though, will let you know as it comes to mind