I use excel with a few different tables to keep things organized.
1. Master ledger. Inventory of all coins (work in progress), listed by country, date, grade, variety, issues, cert, price paid, value, date purchased/sold/sale price, inventory number.
I wish I would have been more detailed on where I purchased. It is just
ebay, bank, other. Best thing I did was list some bulk lots as one item (eg. Box of pennies of 5000 coins). No time to catalog and number each coin.
2. Collection list. Basically a table that shows me highest grade of each coin I am collecting and associated tables for each monarch to summarize each type set by denomination. This is pulled from master ledger.
3. The scary table. Pulls data on cost, value, sold and profit from master ledger. It's surprising how quick it adds up. I might not want to show this to my significant other...
Overall it is kind of neat to see how far I have come, looking at some of the winners/losers and it has inspired me to sell duplicates to reduce investment and free up space for stuff.
Next stage is to photograph permanent collection and label with inv number. Hopefully when it comes time to sell/pass it on, it will be an easier process as all cataloging and photos are done. The hardest part I find in selling off excess coins is taking time to photograph and price, once that part is done, listing becomes a lot easier.