$150 is the price I pay for a Moto Z3 play (of course after a discount from Motorola, which is applied to everybody). The Z3 play might not be as "open" as this one, but it's a very nice phone, rootable, able to install TWRP. So $150 for this phone is a little too much.
Perhaps you haven't read the product description. Here it goes:
An Open Source Smart Phone Supported by All Major Linux Phone Projects
Perhaps you’re in a line of work where security is a must, or a hard-core Linux enthusiast, or perhaps you’ve just got enough of Android and iOS and you’re ready for something else – the PinePhone may be the next Phone for you. Powered by the same Quad-Core ARM Cortex A53 64-Bit SOC used in our popular PINE A64 Single Board Computer, the PinePhone runs mainline Linux as well as anything else you’ll get it to run.
The purpose of the PinePhone isn’t only to deliver a functioning Linux phone to end-users, but also to actively create a market for such a device, as well as to support existing and well established Linux-on-Phone projects. All major Linux Phone-oriented projects, as well as other FOSS OS’, are represented on the PinePhone and developers work together on our platform to bring support this this community driven device.
To me it seems quite cheap. I paid 150€ for my current huawei with all sorts of the usual spyware installed (from google huawei, facebook) that I can't really get rid of. Paying a smilar price for a phone that I can fully control seems a great deal
Being deeply in this open smartphones thing for more than a decade already, $150 for PinePhone is insanely cheap, with practically no profit margins. But I guess somebody will always complain regardless of how low it gets ;)