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.
Yes, I use excel but I am just tracking purchases and premium paid over spot so I have a couple of cell formulas for that and I don't worry about digging up recent sales data.
Sounds like your data would be very interesting. You should post some of it.
I makes for interesting looking but it takes a long time. I might do an excel stacking post sometime, thats not a bad idea buddy