I was searching for the source of arrows but had no luck. In S01 there were some mentions that Oliver Queen made arrows for himself. I think I saw some scenes too of making arrows by Oliver himself (normal ones). But then we saw some custom arrows, arrows with explosives and sound recorder/transmitter.
Now where did these arrows come from?
These require technical skill that Oliver didn't have. He is a drop out. So he can't make cool stuff like Iron man can all by himself. In the beginning of S02 there was a mention that the bow was custom made and was a gift from Felicity. But there wasn't any mention about arrows. And I don't think Felicity made them, there also weren't any scenes of making those arrows (upto S03E02 that I've seen).
There is an option: Queen Consolidated's Applied Science division. But there are 2 problems:
His arrows' carry unique signatures.
In S01 Detective Lance identified that signature and differentiated which one is Arrow's arrow and which one is from copycat Arrow (Merlyn). For this same reason Queen consolidated staff can know who is Arrow, the person that ordered to make them.
In S02 ending portion Oliver lost the company, so he can't use its resources. But we saw in the beginning of S03 that he still got plenty of arrows. So I guess it's not Oliver's company that makes them.
Iron man made his toys by himself, Batman created some by himself and others are made by Lucius, Flash gets his stuff from Star Labs. So how is Oliver getting these huge amounts of arrows, especially custom made ones? Any source where it's explained?