I am a little baffled at the question - where are you looking at online to order from and what is considered outrageous shipping? I am not trying to be flippant at all, but just trying to understand where you are coming from. I had a suggestion as to fittings but then didn't know what you considered too much in shipping.
Grizzly does charge too much in shipping for small parts. So does Rockler, Woodcraft and a few others most of the time. Some charge per item, some don't. I get that.
AS to my suggestion, unless you have Amazon Prime, they may charge too much also. (I have A.Prime) But they give me the best choice and when I compare their prices to HD or Lowes and even Harbor Freight, they are usually equal, AND they do have a larger choice. I have had slow leakage in my air hoses for ages and then found some at Amazon (on the recommendation of a friend) and my leaks have stopped.
As to your mating email fittings, look for quality fittings, look for something like Miltons fittings. These are the quick connect that stopped my leaks that I had on fittings from HD and other sets from HF:
When looking for fittings on Amazon, I look for star ratings + number of reviews (in the 1000's) for a more accurate view.
IF you don't have Prime or the item is not listed as having Prime shipping, shipping might be too expensive.
ADD IN: It might be that you may benefit from changing out the 1/4" flare male to one that is from the same MFG line as the female. I have found that fittings cross MFG lines work just so-so at best.