I churned away from PIA to PureVPN a year ago; today PIA sent me an email offering a US$29/yr subscription (normally it's US$39.95):
For this weekend only, save an incredible 75% when you come back to Private Internet Access, the VPN you know and love. We don’t need to remind you that we’re a values-driven company, battle-> tested in courts with a proven no log policy.
And for the next two days only, you can come back at the lowest-price we’ve ever offered.
We hope you’ll re-join.
The link from the email still worked when I stripped the unique ID. I'm not sure if I believe the "this weekend only" / "two days only", as the content on the website makes no mention of an expiry.