How to change the datatype of a column from integer to money?

I am attempting to convert a PostgreSQL table column from integer to money, but I am receiving the error: >cannot cast type MyColumn to money I have tried these two statements, but just haven't found any real example on how to really do it. ALTER TABLE products ALTER COLUMN price TYPE money and: ALTER TABLE products ALTER COLUMN price TYPE money USING to_char(price, '999.99') How can you change the datatype of a PostgreSQL column from integer to money?