Where I get it doesn't matter as much as how I get it out of the container and what type of container it is.
Some vendors sell it in solid blocks, wrapped in Plastic. Essential Depot is one of those vendors who sells large blocks that way. Many vendors sell smaller amount in plastic jars. With the large blocks, I use a very sharp kitchen knife to cut off smaller chunks, then put those chunks into another container for storage. The chunks inside my plastic container are easy to get out and weigh.
When I have CB in smaller containers (I don't usually, but have in the past purchased that way), I do what others above mentioned, the hot water bath to soften the CB enough to cut bits out of the jar. If I know I"m probably going to need all or most of what's in the jar, I just melt it all in the jar and pour it into my mixing vessel on the scale to get the desired weight.
After the jar is mostly empty, I use the residue as a hand softener. I love cocoa butter for that, more so than any of the others I use for making soap.