I have an upcoming trip to Hungary. They require a PCR test not more than 72 hours prior to arrival.
This is a bit anecdotal because I am sure it will vary by locations, but there is something reassuring in it.
CVS: 24 hours almost to the minute (free)
Walgreens: 34 hours (free)
And I went to one of those clinics (a national chain called ADL) that charge out the kazooie but promise the next business day. They did it in 24 hours as promised but left off the time stamp ... even though I reminded them and they promised .... but a quick email and they sent a new one within minutes.