My college student son wanted a Joker costume for Halloween but couldn’t find one to his liking, so I made one out of a few pieces of thrift store clothing and some fabric paint.

Thrifted suit pieces for the Joker costume
After volunteering to make the costume, I bought a standard-issue grey suit from Goodwill. My plan was to paint it purple and call it done. My son was underwhelmed.
He was adamant that the jacket had to hang down to his knees — and he sweet talked me into agreeing with him.

I am not a good enough seamstress to be able to lengthen a jacket by 18 inches so I went back to the thrift store in search of a knee-length coat. When I couldn’t find one, I decided to buy a second suit jacket that matched the one I already had as closely as possible: same basic size, color, and style. The only real difference was that the second jacket had flaps on the front pockets. (Sorry, I didn’t take a “before” picture of it.)
My new plan was hazy at this point but involved somehow combining the two short jackets into one long coat.
Painting the pieces purple
With all the pieces rounded up for the Joker costume, I bought two 8-ounce bottles of purple craft paint and one 8-ounce bottle of textile medium.

I mixed the craft paint and textile medium in a 2-to-1 ratio. The textile medium prevents the paint from cracking after it dries.

I had to really saturate the fabric in order to get the paint to cover the grey suit.

To prevent the paint from seeping through the fabric, I put a piece of white foam board inside it.

The foam board was too wide to slip inside the pants legs, so I flattened an empty saltines box and used that to block the paint from bleeding through there.

I painted one section at a time, sliding the foam core/saltines box along as I went.

By the time I was done, I had used every last drop of the paint I had bought.
Creating the Joker costume coat
Once I had all of the pieces painted, I cut the jacket with the pocket flaps off above the armpits and threw out the top portion.
The bottom portion I positioned along the bottom of the other jacket.

Fortunately the two jackets were basically the same width so it was easy to line them up.

To hold the jackets in place, I put in a row of pins all the way around.

Then I stitched the two jackets together. (You can see in the photo above I had misjudged how far up I had to paint the bottom jacket. I ended up filling in that extra inch or so after I was done sewing. )
The vest
For the vest, I started with another Goodwill find and some more paint and textile medium.

I didn’t have the right shade of green on hand, so I mixed a little white paint in with the green I had to lighten it up. Then I added the textile medium, just like I did with the purple.

Once again I had to really saturate the fabric to get good paint coverage. I put the white foam board in between the front and back of the vest to prevent seepage.

I painted right over the buttons.

My paint job ended up being a little uneven and grungy looking. I was planning to go back and give the vest a second coat of paint, but when my son saw it, he told me not to bother. He thought the vest looked more authentic — and more befitting of a villain — being a bit grungy and imperfect.

Once I had the coat and vest done, my son tried them on to make sure the pieces fit (they did) and he could move in them. He said the fabric was a little stiff from the paint, but not so bad that it was uncomfortable. (No, the jeans and the red lumberjack shirt are not part of the costume.🤣 )
The finished Joker costumer
Here’s the finished look, right before my son headed out to Freak Fest in Madison. (He even dyed his hair green, which is a little hard to see in the dim lighting of the parking garage where this photo was taken.)

I have to say, the costume turned out better than I thought it would! He got a lot of compliments on it, and now I’m wondering why anybody ever buys a ready-made costume. It’s much cheaper — and way more fun — to create one yourself. Even if you can’t sew (and I barely can), you could still make a costume like this using fabric glue.