In Sharepoint 2010, the "field types" (data types) for list items that could presumably be used for monetary values are Decimal and Currency. Normally, decimal is the preferred data type in C# for money.
But what of this Currency type? Based on its name, it seems it may be the more suitable of the two. Is it?
I could also use integer (where 1225 represents $12.25, for instance) or String (where "12.25" represents $12.25), but the first two mentioned (Decimal and Currency) would seem to be the best bets.
UPDATE
Oddly enough, I was going to provisionally go with "Decimal" in my list, but SPFieldType actually doesn't seem to have a Decimal member available, so for now I'm going with Currency. According to page p. 230 of "Inside MS Sharepoint 2010," though, Decimal is one of the types...???