I am out of both Drum and Keyboard serial 6-packs, so the next time they release something I want, I'll have to reload on both.
SDX, EDX and EZK expansions are pricey. There's little chance I'll accidentally spend over $100 on something I already have. But I could spend less. And have. It is a real problem.
With Toontrack for me, I own basically all of the drum and keyboard MIDI packs that I'm interested in. I buy a 6-pack of serial numbers and pick up anything new that I want. I don't have any need to buy from within either SD3 or EZK.
The best prices I've found for the 6-pack of serials are:
Drums:
https://www.thomann.de/gb/toontrack_drum_midi_6_pack_2.htm Keys:
https://www.thomann.de/gb/toontrack_ezkeys_midi_6_pack.htm If someone knows of better prices, I'm all ears!