This is a good question. I can really only give the view of what I did
A) At the start I made a Concious choice to only play Imperial. Im a huge fan of the Empire in both movies/ books/ comics and the expanded universe. This has made my choices easier (in terms of what to buy)
B) I order online. I try to support my local stores but to be honest Hobbies like this in Aus can get very expensive. I have used online stores to buy say 90 percent of X wing stuff. I start with booko.com.au and use the isbn to track down the specific stuff I want. It makes it easier to budget but of course then you have waiting periods for it to arrive . Ive never not had something arrive.
I think Ive saved easily 300 dollars plus doing it this way. I DO sometimes feel guilty for not supporting my FLGS, but when it comes down to it, I saved 300 dollars or so. That is more important to me.
For a while there is was V hard to get certain ships locally, so I managed to actually do some ship for ship trading for extras I had but had not yet opened. This might be possible for you, if you have such ships.
Like a few posters above me, and because of my exclusive focus on the Empire, I dont really find a huge desire to buy any Scum and Villany so Ive put that money aside to get into Armada (well preorder but close).