The cost of a flu shot varies by location and insurance coverage. As of 2015, the average flu shot for a person with no health insurance averages between $5 and $30. Co-pays for an insured individual usually range from $0 to $10.
Flu vaccines can be received by injection or nasal spray. The injection contains a strain of the killed, inactive virus, while nasal sprays contain a strain of live, weakened virus. After receiving the influenza vaccination, it takes about two weeks to develop immunity to the virus; during those two weeks, an individual is still at risk for getting the flu. Most CVS and Walgreens locations offer free flu vaccines for people with health insurance.