The Materials Trader is your friend -- do a little cross-leveling and it's easy to take advantage of this sale. If you Google "Inara material trader" you'll easily get a link to show you where the nearest ones to you are without having to use the ill-conceived in-game UI for that.
For my part, I love this sale, even though I did a ridiculous amount of engineering earlier this week (naturally!) ...but I'll also admit that I'm a compulsive material hound -- no matter where I'm going in any multi-role ship, I'll almost *always* check out each USS and drop into all that resolve as HGEs, Combat Aftermath, and Encoded Emissions signal sources. And while in supercruise, I scan any ship that comes into my sensor cone. And slup up the mats from all large-hull pirates that are silly enough to interdict me (all the large-hull ships drop nice mats, especially the T-10!). Those activities help break up the monotony a little bit for me. And I usually choose the mats or data type options when running missions rather than just the cash. So I usually, effortlessly, keep around 70-100 of each material and many of the data types (except for the G5 mats, which I rarely seem to get about 40-60.
This is what I need to learn to do! [up]
@Camisade what platform do you navigate the ED universe on?