493 cards + 7 blank cards = 500 cards.
33 of those 493 cards are "placeholder cards", which you may want different sleeves for. 25 of those placeholders (for the Kingdom cards) you probably want the same colour for, so you can shuffle them and deal a random set of 10. Or other stuff like that. The other 8 placeholders (for Copper, Silver, Gold, Estate, Duchy, Province, Curse, and Trash) could be also anything, but something clever would be to find some old sleeves and use them. My FLGS has a box of second hand sleeves at 1p each, and I plan to get 3 gold, 3 green, 1 purple, and 1 red for those 8.