red long sleeve shirt (already had it)
bibbed overalls (second hand shop for couple bucks, dyed denim blue with Rit dye)
white gloves (you can usually find these in a pack of 2 for $1)
mustache or eyeliner for drawing one on
The hat is the challenging part, but I came up with a pattern that is easy, and looks pretty authentic. Do you know how many times I went to a site that promised a Mario hat pattern and all it had to say was "glue a foam M to a red baseball cap"? Many. Lame.
To make this hat you need to gather:
1/3 yard red sweatshirt material
narrow-ish elastic, cut a little longer than the circumfrence of the noggin it goes on
lid to a five gallon bucket
bowl with about 6" diameter
Fold your fabric in half, right sides together. Using the lid to the bucket as a template, cut a large circle. This will give you two pieces. While the pieces are still together, cut a small notch somewhere along the edge. Because this fabric is only stretches one way, you need to make sure that the grain on both pieces runs the same way, or it will not work right. Later you will use the notch to realign the pieces and ensure they are running the same way. Separate the 2 large rounds. Cut a small circle from one of the rounds using the small bowl as a template. You actually want the hole to be a little too big because later we will attach elastic to make a better fit. Also, you want to hole to be offset towards the back of the hat. Using the size of the small hole and the width of the elastic as a guide, cut a long rectangular piece to serve as your elastic casing. The last piece you'll need to cut out is the bill. You should be able to cut this from a scrap. Right sides together, cut a crescent piece. Use your judgement to determine the size and shape. Using the guide below, align the bill and the opening on piece 2 and mark them. You can do the same with piece 4 if you'd like. This takes the guesswork out of lining it up.
Now that you've got the pieces cut out, it's time to get it assembled. Pin both bill pieces, right sides together, and sew along the outer edge. Turn it right side out and sew again about 1/2" from the edge. This will stiffen the bill. You can do it again as many times as you want. Fold piece 4 in half the long way and pin. Align the bill to piece 2 using the marks you made. Make sure the top side of the bill faces the right side of piece 2 (What color was your bobbin thread?). Now, take piece 4 and align it with pieces 2 and the bill. You want the raw edges of all pieces to be together. Pin through all layers as you work piece 4 around the edge of the hole. Starting in the back, sew through all layers. When you get around to where you started leave a little bit not sewn so you can get the elastic in later. Right sides together, align pieces 2 and 1. Pin and sew. Now turn the whole thing right side out. It's a Hat! Feed the elastic through the casing keeping it flat. Tack the ends of the elastic together. Once the elastic is in and everything is even, tack around the band in a couple of places to keep the elastic well behaved. I chose to push the bunchy-ness to either side of the bill and sew through the band and elastic right where the bill attaches. This keeps the bill from wanting to get scrunched up. Go to the back where the elastic came together and tuck everything in nicely and stitch it closed.
Phew...now for the finishing touches. Cut out a circle from the white felt. You want it to fit just between the bill and the seam where the top of the hat attaches. Now cut out your "M". Using hot glue, attach the felt circle to the hat. Trim the threads. You are done!
This hat should last you for a long while. My son wears his to school. He actually wears the entire costume to school all of the time. What are they going to do? Tell him he can't wear overalls? Even though this seems long-winded, it is very easy. I took one for the team and made one that sucked so you didn't have to. Then I made it awesome. You're welcome.