Recommend Tim Tyne's sheep book to start you off. I differentiate between things needed for this batch of sheep (wormer, feed, Clik and so on) and items which will last years, if not decades, like hurdles, buckets, hayracks and so on (most of which, incidentally, will pretty well maintain their value if you decide to sell them later). Used to be you could kit out at farm sales - worth keeping an eye open in your area.