If at the time that a salvaged mech is found, you have no bays, you have the option to buy a mech bay for that mech with MC as normal. Salvaged mechs must be collected immediately after the battle, so you must have enough MC in the amount to buy a mech bay or have a free mech bay at the time of salvage.
Edited by Galahad2030, 16 November 2020 - 11:59 AM.