Wo zai Kmart mai dongxi. Wo mai le duoshao   （ji）zhang guangdie.

"duoshao"  and "ji"  also mean "some" or "several" in there ,but "ji" is always used in declarative sentence and interrogative sentence(spoken language).

"duo shao" always means "how many" and "how much'.

And in declarative sentence "duo shao' is used to emphasize(a huge number of church are in the foggy rain!=duo shao luo tai(church)  yan yu zhong ^_^)      and  means "more or less"

All in all ,in my opinion······· well done  man ~ ^_^