What is Mail In Rebate

[EcoMCG]

I am creating a build on Pcpartpicker and under the graphics card it says: $20.00 mail-in rebate
What does it mean? Here's the link to my build:

PCPartPicker part list: http://pcpartpicker.com/p/2vZ7C

Thanks in advance

-Eco

 

[rgd1101]

http://en.wikipedia.org/wiki/Rebate_%28marketing%29

 

[EcoMCG]

http://en.wikipedia.org/wiki/Rebate_%28marketing%29

Sorry I am really tired, but do I get $20 back? Or Do I have to pay an extra 20?

 

[rgd1101]

noun 1. a return of part of the original payment for some service or merchandise; partial refund.

so you are getting 20 back