Before hitting the gong, I had 59 silver charms and 6 gold. In the wastelands (the final area of the game) I found or bought another 60 gold charms (using up the 29 stacks of 50k gold I brought with me to the wastelands and most of the loot and gold gathered there).
Before the wastelands I also found 24 red (medium) charms, 19 blue (minor) and 1 green (weak).
Anyone can have charms (some people reported pickpocketing charms from soldiers) but the best NPCs to check would probably be Kistandalius or (less so) Blake in Ars Magicana and Corinna or (less so) Mpenzak in Verdistis.
If you quick save before running your mouse over an item/chest/merchant or hitting the alt key, you can identify the item or trade with the merchant, then quick load to get different stats or inventory. This can be done repeatedly to get the best stats or specific bonuses on an item (save after finding good candidates) or looking for specific items (such as spell books or charms) from merchants. Don't waste too much time with this, though, it really isn't necessary to get the best possible equipment.
I also held off using charms until I had better equipment and charms, but by the time I did I was strong enough not to need any additional boosts. The game gets a little easier as it progresses, and I reloaded to make sure I had really good dragon armour and holy sword, etc (which I wouldn't waste much time on playing again). Gold also gets easier to come by, so I continued collecting charms, as well as purchasing any spell books that I thought might come in handy.
