What was the original price of a Browning FN-Inglis No 2 MK1 in 1939 or another Browning handgun in the same era?

Browning, FN, and Inglis really describe different products. I assume you are referring to the Inglis version of the FN P35 pistol. Inglis, in Canada, did not begin manufacture until 1940 with 100% of production going to military channels. There would not really be a 'retail' price. The FN-manufactured 'Browning Hi-Power' commercial pistol was not introduced to the US market until 1955. Pistols sold before then would have been FN commercial pistols or surplused military pistols imported through secondary channels.