This simple and easy to build wood easel frame costs $3 - $4, can be built in 5 minutes if you are comfortable with a circular saw and a power drill, is sturdy and folds flat or can easily be completely disassembled. Instructions are given for two size frames, which are based on using a 6' or 8' long piece of 1 x 2 pine.

The 6' piece will create an easel suitable for an 11x14 canvas
The 8' piece will create and easel suitable for up to 16" x 20" canvas

Step 1: Materials

Materials

6' or 8' piece of 1" x 2" pine (note, 1" x 2" is actually 3/4" x 1.75" due to finishing losses)
3/8" dowel
1 1/4" screws (any type will work)
string

Tools

Saw (circular saw is faster, but a hand saw will work)
Power Drill

Step 2: Cut the Pieces and Drill Holes

Saw

First cut the long piece into four pieces. Mark and cut at the locations below. The cuts don't have to be perfect, within 0.5" will be fine. If you are making multiple frames and using a circular saw, measure one board and then line up a few of them at once for the cutting.
- The order of the pieces are: front, front, back, cross
- 6': pieces 19", 19", 18", 16" / mark at 19", 38", 56" and the last would be at 72", OK if long
- 8': pieces 27", 27", 25", 17" / mark at 27", 54", 79" and the last would be at 96", OK if long
On the front pieces make another cut, from halfway on the end until ~ 2" up on the side. It is OK to just estimate this. See photo.
The red part: I didn't do it on the real photos, but if I did it again I would also cut off a section of the back piece, the area shown in red, because it can poke into a tall canvas.
Cut a piece of the 3/8" dowel, at least 3" long

Drill

Drill a 3/8" hole through the middle of the angled front face at a 90 degree angle (i.e. perpendicular to the angled face). Do this for both of the front pieces. If you are not comfortable using a drill, then start with a 1/8" hole to make sure you can get it in the center, then switch to the 3/8".
For the back piece, drill 3/8" holes through near either end as shown. Also put a hole on the non-angled end of the flat side of the front pieces as shown.
Drill some 1/8" holes on the cross piece as shown. These will give you options when you mount it on the frame, will make it easier to put a screw through, and will prevent the wood from splitting.

Step 3: Assemble the Pieces

Now assemble the pieces. You may need a hammer to tap the dowel through the boards, or just push it against the ground. It should be a snug fit so that it doesn't slip out. If you have trouble getting the dowel started then round off one end with sandpaper or whittle the edge.

Use the 1 1/4" screw to hold the cross bar onto the front pieces. You can adjust this later many times for a different height canvas.

Note - the red part is the section that would be cut out during the cutting step if I were to make another.

Step 4: Put String Along the Base. Final Photos

Run a string through the holes at the bottom to prevent the back leg from sliding back. Now you are ready to paint.

The images above are of the larger easel, made from the 1 x 2 x 8' piece.

Tip: Save the little angle pieces that were cut off and use them to prop up the canvas if you paint the bottom of it, this will help keep the canvas from sticking to the easel.