It is not a product (linear), it is an exponential (which grows insanely fast)!
Cheap stuff will not be affected too much, but expensive stuff will skyrocket:
Some numbers:
Tribal warrior outfit: 21^1.35 = 60.95 (3 times as expensive as it was)
Mail Hauberk: 55^1.35 = 223.6 (4 times as expensive as it was)
Heavy Kuyak: 102^1.35 = 514.76 (5 times as expensive as it was)
Milanese: 376^1.35 = 2995.7 (8 times as expensive as it was)
So with 4k gold, you could buy eg:
Before, 10 milanese, 40 kuyaks, 72 hauberks or 190 twoutfits
Now, 1 milanese, 7 kuyaks, 18 hauberks or 66 twoutfits
Or, a milanese costs the same as
Old: 4 kuyaks, 7 hauberks, 19 outfits
New: 6 kuyaks, 13 hauberks or 50 outfits