How long does it take to get an appointment for biometrics?

Pretty much what the title says. How long will it take to book an appointment to get my biometrics taken.

EDIT: just to clarify I mean how long after I submit my visa application until I get my biometrics appointment (roughly)

In the US?  In the UK?  Free or paid for (if UK)? 

In the US?  In the UK?  Free or paid for (if UK)? 

I'm switching from a marriage visa to a family visa and once you submit this application you get given an appointment to get your biometrics done in order to get your BRP. I was just wondering I soon I could get an appointment as I cannot submit my application yet. This is for the UK and I believe it's paid for in the visa fee.

“Free” appointment, two to three months but they are unicorns and hard (near impossible) to snag.

c£60 to £100 for an appointment will usually get one in 2-3 weeks.

£800 will be a week or two with a 24 hour turnaround for approval.