Dieter has a huge selection of toroids and magnet wire for an extremely low price. I was really surprised by the prices he offers as I used to pay a fortune for the same things from other distributors. At first, I thought the prices were a little too good to be true but I tried out his store, paid with PayPal and received the goods within 2 business days, no problems or catches at all!
Some other things I found in his store were Intermediate Frequency (IF) transformers. IF transformers are also referred to as IF cans because of the metal can shield around the actual inductor. The formerly big players in the market for IF cans, Sumida and Toko, discontinued their production a long time ago. Since then, it can be a hassle finding a reliable and inexpensive source for these products. I asked about the reliability of his stock and Dieter indicated: “All parts listed on my website are expected to last as long as I do.”
Links and Sources:
 Dieter Gentzow, W8DIZ: http://www.kitsandparts.com/