We estimate a model of consumption and money holdings with multiple means o
f payment, using data for the United Kingdom. The model describes a technol
ogy for transactions, where money and credit are imperfect substitutes. It
allows us to identify shocks to the transactions technology. We evaluate th
e value of long-term changes in the payments systems to the representative
consumer, as well as the welfare cost of inflation from 1977 to 1998. The e
stimates allow us to evaluate the welfare costs of inflation of this period
. The model also has implications for consumption-smoothing in response to
monetary shocks.