If you want charms i highly recommend you to do something else, a bonefire random comes about ever 10-15min and gives about 5 charms total. Which is very slow exp if your going to train summoning.
Wrong. It's also called a fire spirit.
The odds are 1 in 100 logs burnt. You can burn around 1.2K, more or less, per hour. That's an average of 12 fire spirits per hour. Now you can guess how many charms you get per hour as I have no idea of the odds and I haven't done it for long. You get 1-3 Gold, 1-7 Green, 1-3 Crimson and 1-2 Blue charms. The odds of getting any, I don't know. I'd say 3-4 fire spirits gets you blues, while green and gold every 1.5 Spirit, crimson probably 2-3.
So based on my estimates I'd say anywhere around 3-8 Blue charms, 4-18 Crimsons charms, 8-56 Green charms and 8-24 Gold charms. The first number is the lowest you can get with the odds I've given above. The second number is the highest you can get based on the number of charms that can be given each if you got the most out of each based on the odds of getting spirits.
So in short, I'd say 5 Blue charms, 10 Crimsons, 30 Green and 15 Gold.
Edit: People should stop telling him what he should do. What if I told everyone to do Glacors because that's around 40k Summoning exp in charms. Not everyone can do it obviously as they don't meet the requirements. He could be a skiller.