American Express now dominates the "member card" arena, providing thousands of customers with cards that require the monthly balance to be paid in full.

Likewise, we can estimate savings, and the changes, from average monthly balances.

The average debt among those with a monthly balance is $9,000, said the Consumer Federation of America in a recent report.

American Express card holders are expected to pay off their monthly balances in full.

Requirements for free checking: For regular, an average monthly balance of $3,000 alone or $6,000 in combined deposit accounts.

Requirements for free checking: For regular, $3,000 average monthly balance alone or linked.

For interest-bearing, $5,000 average monthly balance alone or linked.

Requirement for free checking: For regular, an average monthly balance of $1,500.

For interest-bearing, $3,000 average monthly balance in checking or $5,000 in combined accounts.

After the first year, the accounts had an average monthly balance of approximately $800.