You know, you could do a quicky using 16' 4x4's.. sink em about 4-5 foot in. Then, use 2x6's or 2x4's to make runners down the long sides. And use 2x4's across as supports for roofing tin. They make the tin in many varieties I like 26" ( 24" with overlap '5V' style.. comes in lengths from 6' to ??
An easy one would be 4 4x4's.. could be square, or rectangular. You will want a roof pitch to shed water. a longer one can be done by adding another couple 4x4's
I've made many of these on my property as sun shades for the animals. For ease, you can use the metal hanger hardware, for the 2x4's, they have built in guides for toenailing, etc.
You should be able to put one of these up in a day easy, counting the trip to lowes.
If all you need is temporary, you can throw a square, or small rectangle ( 4 post ) up for probably 320 bucks ... , for something like a 10 x 12, w/ 2x6 side rails and front /rear cap 2x6, and 2x4 braces for the tin ( 2' apart is fine for the braces.)( remember, front and rear 2x6 brace acts as leading and ending edge for the tin, leaving only 5 more cross braces needed to make up the 2' spacing down the 12' length. (4) 4x4 16' posts,( 5) sheets of 24" x 12' tin, (2) 10' 2x6, and (2 0 12' 2x6, and ( 7 ) 10'4's... ( 5 ) of them for tin braces, and (2) cut into 2.5' pieces as braces for sway on all 4 corners.
I built one exactly like this. Also, I used a caulking gun, and cheap mastic caulk to join the seams on the roof tin, and this also figures the roofing nailes with the little rubber piects for sealing, some 10penny nails, and the hardware straps if you need them.. That is approx. what I paid... put it up pretty quick too.... if you had help.. even a kid or a wife, it foes up 1.5x faster.
This is a cheapy friction pile structure if anyone asks you.. in some agricultural places, permits arent even needed for a structure like this... in my county it wasn't anyway.
Soundguy