There would be giant smiths, seamstresses, etc. They might go on "raiding expeditions" into the forest or fields of flax to steal material for clothing. I can even see a Common-speaking Giant making a deal with a farmer.
Giant: "Give me flax, or this loincloth gets holes in it."
Farmer: "It's already got holes in it. I can see your ... okay, take all you want. Just get that thing away from me!"
It also depends on intelligence and civilization level. I figure frost giants are civilized enough to have small villages (set up as well as cities, but with fewer individuals due to small population size) and mines. Their smithies could melt down weapons taken from foolish downed adventurers and eventually make huge axes from them. Many giants would have a few levels of commoner, expert or something else that makes them more productive. Like humans, most would have one or a few class levels.