Beware of “free” or super low-cost VPN services. Proper VPN services are not cheap to operate, so the revenue for the service has to come from somewhere. And there are countless “free” VPN services that are anything but, as we’ve seen with 911.

In general, the rule of thumb for transacting online is that if you’re not the paying customer, then you and/or your devices are probably the product that’s being sold to others. Many free VPN services will enlist users as VPN nodes for others to use, and some even offset costs by collecting and reselling data from their users.

All VPN providers claim to prioritize the privacy of their users, but many then go on to collect and store all manner of personal and financial data from those customers. Others are fairly opaque about their data collection and retention policies.

I’ve largely avoided wading into the fray about which VPN services are best, but there are so many shady and just plain bad ones out there that I’d be remiss if I didn’t mention one VPN provider whose business practices and transparency of operation consistently distinguish them from the rest. If maintaining your privacy and anonymity are primary concerns for you as a VPN user, check out Mullvad.net.

Let me make clear that KrebsOnSecurity does not have any financial or business ties to this company (for the avoidance of doubt, this post doesn’t even link to them). I mention it only because I’ve long been impressed with their candor and openness, and because Mullvad goes out of its way to discourage customers from sharing personal or financial data.

To that end, Mullvad will even accept mailed payments of cash to fund accounts, quite a rarity these days. More importantly, the service doesn’t ask users to share phone numbers, email addresses or any other personal information. Nor does it require customers to create passwords: Each subscription can be activated just by entering a Mullvad account number (woe to those who lose their account number).

I wish more companies would observe this remarkably economical security practice, which boils down to the mantra, “You don’t have to protect what you don’t collect.”