What merchants sell praxis kits?
Solution 1:
Base Game
The total number of merchants selling Praxis kits in the base game (i.e. before any DLC) is
one (Tars)
and the total number of kits sold is
four
with
two available before Utulek (aka Prague 1), one available between Utulek and GARM (aka Prague 2), and one available after you visit TF29 after GARM (aka Prague 3)
DLC
-
Desperate Measures: This pre-order standalone add-on has no merchants of any kind (let alone Praxis sellers). There are no credit chips or sellable-only pickups to be found. (The designers of the hacking puzzles, however, forgot to remove some of the bank account rewards.)
-
System Rift: This add-on has no merchants of any kind.