Using CONVERT function

[Bill]

I'm getting the following error:

[Microsoft][ODBC SQL Server Driver][SQL Server]Disallowed implicit
conversion from data type varchar to data type money, table
'bill.dbo.cart', column 'price'. Use the CONVERT function to run this
query.

Does anyone understand this function and how to use it? I'm trying to
pull a quantity value from one table, multiply it times a price to get
a total cost, and then stick the product into the new cart table.
However, it seems like the quantity, which was a varchar, but has
since been converted to a numeric, is still being viewed as a varchar.
Can someone help me on this?

Thanks a million,

Bill