I wanted one of those, and all the catalog folding stands were upwards of $200 - pretty steep for something I'd only use as shows and would need to carry from the rig to our tack area..
So, I got creative. While at one of those weekend tool sales (Homier), I bought a flat metal wagon , the kind they have at nurseries to carry plants. You can also buy them online at their website.
Wagon
Price of wagon: $29.95
Then I bought a milking stand head piece - if you know someone handy, you could whip one up out of angle iron or even 2 X 4's pretty cheap. Here's one from Caprine Supply:
Head Piece They also sell kits to build your own portable stand, but again, over $200
Price of headpiece: $95
The headpiece bolts on with two bolts and wingnuts.
I have a wheel chock that locks it in place.
Total price: About $125 above, (we built our own head piece from 2 metal posts for about $5 and a little welding.)
Best part - you can use the "stand" to carry all your other tack!