Stick built.

What happens when you discover the shockingly high price of the wire fencing you'd planned to use to trellis your vines?  You improvise.

Luckily for us, we had a yard full of deadfall from the pecan trees thanks to all those windstorms in May, so I went out back with a little hand saw and got myself some building materials.

I recommend burying the bases at least 6" and lashing the tops together with some twine, at least until the vines grow up enough to secure the arch.