I have other ways of converting for local currency, but that would be game specific, along with technology level. That is why I look at using a fixed quantity of gold for the Imperial Credit, such as it is, for local currency conversion.
With lower Tech Level worlds, up to Tech Level 5, having a metal-back currency, Imperials trading on those worlds find things very expensive. Up to 1934, gold was $20.67 cents per ounce in the US. In the UK, the official exchange rate was $4.875 Dollars to the Pound Sterling, so go was about 4 Pounds, 5 shillings. However, that is what I use in my own universe.
Well now, in Striker terms, the factor would be, it depends.
The Imperial credit converts a LONG way in local Tech 5 credits.
However, buying anything above Tech 5 is even more costly.
It would be like selling beads for getting Manhattan Island and say a bunch of animal skins, but having to pay a steep price in gold to get a full set of muskets plus ammo and repair kits shipped in from Europe.
Buying local tech, you buy like a poobah.
Shipping in laser rifles at Tech 5, you pay like a hermit on the end of a bush pilot delivery in Alaska.
The Striker example has a starport B Tech 6 customer buying a 1000 Cr item from a starport A Tech 8 world, works out to 3750 Cr (plus 20% maintenance per year for every year the higher tech item has to be maintained on a lower tech world).
Reversing the buy, buying the B6 item on an A8 world, would be 266 Cr. While the rules do not have a provision for doing that, I would tend to apply the same 20% maintenance rule for lower tech levels since the ability to shoe horses, repair IC engines or other tech that largely does not exist in a fusion/grav world would be similarly expensive and the realm of rare preservationist specialists.
Think maintenance for WWII flying heritage aircraft or steam locomotives for an example.
Certainly not a perfect model, and I think the idea of using this for normal item purchase gives people the heebie-jeebies, but boy it lets you know in no uncertain terms when you have arrived at the boondocks of space.
Hmm, let's say we were to buy a laser rifle at the local Little Green Men weapon shop after they opened trade with us.
They shipped from an A10 origin to our E8 world.
That's a 5x markup, so 5000 LGM Cr of laser rifle and power pack becomes 25000 local Cr plus 5000 local Cr of maintenance.
Gets REALLY fun if you denominate all interstellar transactions in CrImp, A15.
Although to be fair one should probably use the Striker tables as 'total cost to acquire at end retail point' including all that shipping and broker/middleman cost, and the TCS tables for currency conversion including shipping and passenger fare.