fee for porting and another for keeping the number?

[noob]

I know that porting is $20, but is it another $20 to keep that number? I am confused because of this:    Your Google Voice number will be replaced by the number you are porting. It will remain on your account for 90 days (you will be able to make it permanent for a one-time $20.00 fee

[Rick]

No.  They are offering to let you keep your initial GV number.