I use a lot of the Harn economics and related rules for my 30 year Majestic Wilderlands campaign.
I am starting up another campaign and for various reasons I am using Swords & Wizardry instead my usual GURPS as the rules. Swords & Wizardry is a retro-clone of the 1974 Dungeons & Dragons rules. I recently wrote a supplement for Swords & Wizardry called the Majestic Wilderlands which is the main reason I am using S&W in the campaign.
http://www.swordsandwizardry.comhttp://www.batintheattic.comI am adapting the price list I use to Swords & Wizardry. The original version for GURPS is based on the Harn Price List and uses the silver penny as the primary currency.
Now what of interested to everybody here on a Harn forum is that I am finding out that 1 silver piece in Swords & Wizardry equals roughly 1 silver piece on the Harn Price List. For example a Harn Broadsword is about 125d and a S&W Longsword is about 15 gp or 150 sp. Where items corresponds some are higher and others are lower. It breaks down on Chainmail and Plate tho. The Harn version are far more expensive than the S&W version.
Where this makes it really nice is that I can port over prices for things that are not covered by Harn notably magic item creation and the like and just multiply by 10 get the equivalent in silver pennies.
So for those of you who are interested in alternative RPGs to run Harn with I thought you would like to know this. What makes is notable that this doesn't work out as nicely for AD&D and it's retro-clones.