You using excel? I used to update mine every month for every coin, as my stack grew it was less fun. I searched each coin on ebay and filtered to sold, lowest price and buy it now. I would pick the first coin within a 2 week window and use the sell price minus 20%. The data is great but it can take upto an hour sometimes and thats going really fast at 3-4 coins a minutes. I changed it this year to every 3 months instead and will go from there.

Thanks for commenting.