Retainers Included in Invisalign Treatment Program?

Most of the time, the fee is separate from the Invisalign, but part of the "case fee". If you were to call to shop fees for Invisalign, you would be told something like "full cases are $XXX". Most of the time this quote would not include the initial exam, records and retention program.
When contacting an office for care, that would be a good question to ask. Some offices do NOT charge separately for everything, but fees end up being in the same range. Offices that offer Invisalign at a discount tend to charge for the steps, and offices with higher fees for Invisalign tend to include everything.

There are several types of retainers. The one I use is Vivera which is very similar to your aligners in design. You get 4 of them sent to your house over a one year period. Each one should be worn for 8-10 months. So it turns out to be about a 3 year program. Love it. Don't use the Invisalign retainers thru their company. They don't last very long.