I don’t mean this in a snarky way at all, so please don’t take it as that, but I have to ask...
...why do you feel the need to keep them away?
And the reason I ask is because, in my opinion, they are now your sets regardless of how you purchased them. At least, that’s how I view my collection. Whether I got the set at a store, online, through Bricklink, from the Marketplace here, or some other way, as soon as it joins my collection it is an equal among its friends.
^ Add that to the fact that they seem so easily available the past couple of years (at least where I am), and they’ll really sit at $5 or even $6. The amount of TLNM and TLBM2 on shelves at my Targets and Walmarts is crazy. Last time I remember a series being even a little scarce was S14. Since then, each series has been stocked well enough that there are a great deal available for the next two (even three) series to come out. I think it was S16, Disney, TLBM, and S17 that were all on shelves at the same time in my area. Some of the Targets had them falling off the display they were packed so tight.