black poly pipe, with plastic barb fittings and pipe clamps.
best bet is to dig up the floor, and install "frost free" hydrants at each location.
frost free hydrants, the valve itself is located a few feet deep under the ground, and when you turn off the hydrant any water in the pipe above the valve drains out down below ground. and in that keeping any water that would be above ground from freezing and cracking/busting pipes.
frost free hydrants only work if they can drain water out of them, if you attach a garden hose or like to them. and do not disconnect the hose... well something going to freeze crack / burst. and it could be hose or hydrant. (granted a 2 to 3 feet of hose, that stretchs over the fence and into a stall or lot or what not, is not going to harm anything, or less end of garden hose is submerged under water. everything just needs to drain of water, when ya shut off the hydrant.
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cheap and easy, no such thing with plastic or any type of hard pipe or hoses.. the pipe may seem cheap, but once you hit those fittings and more so valves. BOOM! there went your budget a few times over.
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to note it, PEX is just not a single type of material, there are wide variety of PEX piping out there. cheaper stuff and used a lot is the black poly pipe with barb fittings and pipe clamps.