From my ship, I can purchase things that are available for purchase on the Citadel, but there is a 10% markup. Right now I can purchase from Sirta Supplies, Kassa Fabrication, and Spectre Requisitions.
I've found the shops for Spectre Requisitions and Sirta Supplies on the Citadel, but I can't find the one for Kassa Fabrication. I'd like to buy from the Citadel rather than my ship so I can save 10%. Where is it?