By end mill I am assuming you mean a milling machine? As Tom suggested above purchase price would be a good starting point, other than that you could use the classified/kijiji listing of similar machines for current market prices.Our MakerLab has recently purchased a lathe and an end mill. How do you get the valuation of these items if we needed it for insurance purposes?
Using the purchase price was what we thought too. The insurance is fine with this but asked to get a replacement price as well.