Not that anything from Tag is cheap but give them a try. Other than that I know people who have attended courses at other airlines for a reasonable fee.
Ask your local Airport fire service if they conduct first aid courses. A lot do.
With the utmost respect are you flying? If you are indeed unemployed save the expenditure until you have a job. The employer should do it for you, otherwise it will take you a couple of days to address prior to starting employment and your CV doen't need to reflect this surely?!
To my best knowledge CRM needs to be conducted in an approved manner so it would be hard getting a freelancer to sign you off on your own. Happy to stand corrected though.