What kind of tubing and for what purpose?

It's for my drip irrigation system. The 1/2" black line tubing that you connect 1/4" tubing and emitters to. To water individual plants. Micro irrigation system.

Often hardware stores sell what you want, usually stocked close to the drip irrigation supplies. You may want U or J shaped wire anchors.

I have found that the wire anchors bend. I'm putting into hard ground.

that would probably work

I make my own for about 5 cents apiece. I buy 14 gauge galvanized wire in 100' rolls:

https://www.homedepot.com/p/OOK-14-Gauge-x-100-ft-Galvanized-Steel-Wire-50142/100200924

I cut it into one foot pieces with a 45 degree end so that it's pointy, and bend it with a pair of needle nose pliers:

I have hard ground, too, so I use a pliers to force it into the ground without it getting bent:

You grasp the bottom of the wire about an inch or two above the bottom and shove, using both hands if you need to, then you move up an inch and shove again. Repeat until it's all the way in. You can also soak the ground with water a bit to soften it up first, and you can go with 12 gauge wire for a beefier hold-down, but it's harder to bend.

Camping department: tent pegs

That sounds like an excellent idea. I will head off to the sporting goods store tomorrow.