Yeah, I second that; Bon Cool is pretty awesome. Though there usually isn't much overlap between what they carry, so it shouldn't be much of an issue. The downside to Bon Cool (at least since the last time I ordered) was the extra fees versus a flat 13k yen. My first order, they charged me shipping, national tax, and a Paypal fee. I think they only charged me shipping and maybe the Paypal fee the second order, though. My first order came with a free double cover (a Homura, strangely enough, since we were just discussing Madoka covers) and my second order had one cover for 40% off.
Fuuuu... Another cover I missed just for starting this hobby too late. Almost makes me regret my spending habits on my other hobby.
That's pretty much the main thing I've learned about this hobby. When I first got into it, I had so much catching up to do, and I bought a ton of covers I had missed out on for ridiculous prices on YJA. At this point, I have the majority of the released covers I'd like (except for some really rare ones/ones I haven't seen) so my YJA purchases have stabilized to event covers and the occasional good deal. Pre-ordering is absolutely the way to go if you can. Unfortunately, with so many covers coming out, even then it can be hard to pick and choose what you want to buy. I usually try to prioritize then, to pick up the covers I think will be expensive on the resale and skipping over covers I think will have sufficient supply.
And 16k after proxy fees would probably be in the $240 range. >_>