Just because you're a female Teenage Mutant Ninja Turtles fan, doesn't mean you are stuck dressing as April O'Neil.

Both of these costumes are quick and cheap to make and will have you terrorizing the turtles at your next Halloween party.

Step 1: What You'll Need

For the Shredder:

bike helmet - $0 - used helmets are easy to find for free since they're not supposed to be sold for safety reasons
foam camping mat - $0 - found in the trash (check freecycle, craiglist or your parents' garage)
grey dress - $2 - purchased at a charity sale
purple fabric - $6 - purchased at a charity sale
craft foam - $5
silver paint - $7 for 2 bottles
thin cardboard - $0 - from the recycling bin
acrylic floor finish - you'll need less than a quarter of a bottle
velcro & elastic - already owned
epoxy & glue gun
black belt, tights and boots - already owned

For the Foot:
Leftover materials from making Shredder
Black outfit
Sword or other ninja weapons

Step 2: Sewing Shredder's Outfit

If altering a dress seems like too much work, purchase a grey tunic or short dress that fits you and you can skip all that sewing. The dress I found was way too big and baggy, but it was only $2 so I didn't mind putting some effort into fixing it. I'm not a very good seamstress, so if you're looking for good instructions on taking a big baggy dress and turning it into something flattering, there's probably much better instructables for that (like this or this).

First set up a dummy with your dimensions. If you don't already have a dressmaker's dummy, you should try making one from duct tape. Put the dress on the dummy and pin the seams until you are happy with the fit.

I removed the sleeves and shortened the skirt so it would look more like Shredder's tunic.

Carefully remove the dress from the dummy and sew up all your new seams and finish the edges. Try it on to make sure it works and then alter if needed.

Lay out your purple cape fabric. Fold it over and draw out a curve for the top of the cape. You want the cape to be slightly wider than your shoulders. Decide on how long you want the cape and then cut it out. Test out the size and then cut an opening for the neck.

Finish the edges and sew the cape to the dress along the back of the neck and gathered at the shoulders.

Step 3: You Can't Be the Shredder Without Blades

There are several good tutorials online for making foam armour. SyntheticChelovjek has a very good instructable on the process.

Create cardboard templates for all of Shredder's metal pieces. Cut out the cardboard shapes and test them for size. Adjust as necessary.

Trace the templates onto your camping mat or similar foam. You will need 2 shoulder pads, 2 shin guards, 2 forearm pieces and 2 hand pieces.

Carefully cut out the shapes with an exacto knife (scissors will work but the edges won't be as clean).

To create the round shape, heat up each piece with a heat gun, oven or stove burner and then press it onto a curved surface (mailing tube or your leg/arm). Be sure to work in a well ventilated area and take all necessary precautions to avoid inhaling the toxic fumes that may be released when the foam is heated up.

Cut out blades out of the thin cardboard. You will need 4 for each shoulder, 5 for each arm and leg and 2 longer ones for each hand.

Cut slits into the foam pieces and insert the cardboard blades.

With a paint brush, apply white glue over all of the pieces to seal the foam and secure the blades in place.

Once the glue is dry, paint with silver craft paints. I used two coats.

To make the armour very shiny and to give it a bit of extra protection, cover with floor polish. I used Pledge with Future.

On the back of each piece, cut notches and attach velcro straps. I used Gorilla Glue epoxy for the smooth side and hot glue for the fuzzy side.

To attach the shoulder pads, sew a piece of velcro to each shoulder on the dress.

Step 4: The Helmet

Heat up thin craft foam and use it to cover the bike helmet. Secure it in place with a glue gun.

Just as with the armour pieces, create a cardboard template and then cut out a piece of the camping mat in a pointy T shape.

Heat up the foam and wrap it around the helmet. Use the glue gun to secured it in place.

Cut 2 rectangles of thin craft foam, long enough to wrap around the helmet. Glue them together along one long edge with hot glue. To simulate the hinges, glue down small rectangles of foam on the joined edge.

Glue the craft foam to the helmet with more hot glue.

Apply a coat of white glue to the entire helmet.

Once dry, paint 2 coats of silver and then top with a shiny coat of floor polish.

For the face shield, use a piece of craft foam stapled to an elastic strap (an elastic hairband would work). Apply glue, paint and polish as with the other pieces.

Step 5: The Foot Soldier

The Foot Soldier's costume consists of a hood in 3 parts plus a belt. The rest is simply a black outfit you can pull from your closet.

Since I didn't have much purple fabric left after making Shredder's cape, I first made the hood from scrap fabric to test the fit.

The first part of the hood is a balaclava that goes over the head and has opening for the eyes, nose and mouth. While the Foot in the cartoons never needed a hole for their mouth, you're probably going to want to drink, so make sure you can at least fit a straw through.

Fold your fabric so the seam will be along the back of the head. Cut everything out, sew it together and finish the edges.

The next part of the hood is an oval or diamond like shape. When you cut the opening for the head it's shape will resemble something else. Finish the inside and outside edges. This part sits over your shoulders.

The third part is a strap with velcro on either end. It should fit snugly, but comfortably around your neck.

The belt should be pretty self-explanatory.

Cut a foot symbol out of red craft foam and glue it to the hood. If you are making several foot soldiers, it is helpful to make a foot stencil.

Make the arm guards the same way you made Shredder's arm guards, just without the blades.