Currency- Some Ideas
In a previous post, on the old boards, I put forward the idea of a "Pony Standard" in silver - this translated into converting values from standard DnD prices at the rate of 5 gp (DnD) = 1 silver penny (ME). I have actually modified my position somewhat, and now I'd advocate a flat conversion of 1 silver penny = 1 gp (DnD). The reasons are as follows:
1) I'm assuming that money was NOT minted in the Shire or Bree - neither had a main administrative or ruling centre, so it's almost unthinkable that coins were produced. Currency in circulation would be old - from Arnor, or possibly Arthedain, Rhudaur etc. It would be rare, and have a larger value because of this.
2) If the default setting of the d20 conversion is early Fourth Age, then Arnor is re-established, a mint exists (at Annuminas or Fornost), currency is regulated and its availability is higher. The economic boom which accompanies the reign of Elessar would most likely cause inflation - hence devaluing the currency, from the old "Pony Standard." The economy of Bree, once sluggish, would be stimulated by the new regime.
3) Simplicity. All prices in the PHB which were in gold, are now in silver pennies. This still has the effect of making gold very valuable. Gold coins would be VERY rare.
Subdivisions of Currency
If the Dark Age England model of currency were adopted, then 1 penny would weigh 1/15 of an ounce: the Carolingian penny is slightly lighter. It is reasonable to assume that the penny is divided into quarters - the word "Farthing" is current in the Shire (as in "North Farthing" etc.). "Farthing" is presumably a translation of whatever the Westron word for "a quarter of a penny" is, in much the same way that "Brandybuck" is a translation of "Brandagamba" etc. (See Appendix F of LOTR). Gold coinage existed, as Bilbo's gift to Sam at Rivendell testifies. Assuming that the value of precious metals relative to each other is the same in ME as in DnD (1:10:100 Copper:Silver:Gold), the following schema seems logical:
Copper Farthing: A medium-sized copper or brass coin weighing 1/6 of an ounce. 96 to the pound.
Copper Halfpenny: A large copper or brass coin weighing 1/3 of an ounce. 48 to the pound.
Silver Penny: A small silver coin weighing 1/15 of an ounce. 240 to the pound.
Gold (Piece? Crown?): Small gold coin weighing the same as the silver penny (1/15 of an ounce), but 10x as valuable.
or
1 gold crown = 10 silver pennies = 20 copper half-pennies = 40 copper farthings
Note that a copper farthing is still relatively valuable (equivalent to 2 1/2 sp in standard DnD terms), but this is very much in line with Dark Age and Middle Age currency - it simply isn't worth a ruler's time minting very low value coins. Note also that if this weight of coins is used, then metals are FAR more precious than their DnD counterparts - there are only 50 coins to the pound in DnD. Gold is effectively 48 times more valuable in Middle-Earth.
Hacksilver etc.
It was common practice, historically speaking, to cut coins into quarters or use bits of jewelery as currency - in fact many coins were scored to make this practice easier. The weight of metal (copper, silver etc.) was much more important than the actual type of denomination. In order to simulate low-value transactions, a denomination as low as a quarter of a farthing could be available if this method were adopted.