What's expensive? PTP is widely supported on commodity hardware these days. I think most Intel NICs support it, quite a few Realtek and a lot of embedded stuff, down to even MCUs like STM32.

Even if you want a NIC with a stable oscillator or GPS inputs to act as a grandmaster, you can buy an E810 with the necessary hardware from eBay etc. for a few hundred or DIY something yourself much cheaper.

Switches that properly support PTP are expensive, at least for now.

You can achieve microsecond accuracy with a lot of non-timing-specific networking hardware, but it's around as good as you get with modern NTP...

To get sub-microsecond, you need hardware that supports transparent/boundary clock and doesn't just 'say' it does, but actually does (vendors have stamped PTP support on things that definitely don't account for time correctly internally!).

out of dozens of laptops and computers we have where I work, we have maybe 3 that have a PTP-compatible NIC.