I have started building my own to save cost, it is not worth the time for a few short sections of plaintrack but large amounts may be.
I use marcway track componatnts which are basicly copper clad paxolin with peco type nicklesilver rail,
I got some plans sent to me by another forum member, and have made two turnouts, the cost was around ten pounds for componants for the two , plus my time which was around ten hours, I also made a bespoke crossing, which I could not buy at the angle I wanted, for less than £200, the parts for that were around £20, straight plain track would be around £1 per foot, it would be cheaper in brass but brass is a sod to solder, most American modellers build their own track with wooden ties and spikes but dont know how long that would last outdoors.
The good thing about it is that electrically it is simple to wire and once laid does not move about like flexi track.
Pete