Why pay money for one when they're pratically free to make?
I have seen the "TOY" versions and although they have a sound chip, they look kinda slim, youknowwhatImean?
So, to save the landfills from a few extra polystyrene bottles that will decay by the year 2539, you can make one yourself (and it looks pretty good too) I used to make these years ago and have yet to see anyone post an instructable so here goes.

Step 1: What You Need

To start you need an empty Laundry detergent bottle (with cap). Any mid to large size bottle will do. A few years ago they used to come with larger caps that worked really well, but the new bottles are still nice looking. You will also need:

-Silver or gray paint (I used silver spray paint)
-Red paint (again I used spray paint)
-two small wood or sheet metal screws
-Sharpie or marker
-scissors
-screwdriver
-a large piece of wood/ wall paneling/ or cardboard will be used for tha blade. I used some scrap wall paneling

Step 2: Clean Your Bottle!

After thoroughly rinsing out the bottle remove the cap and use it to trace a circle on the left side of the bottle (as shown). The soap gets messy and would prevent the paint from sticking. Let it dry out too.

Cut out the circle carefully staying just inside the line you drew. This way the cap can be screwed in without any need for glue. Save the Circle you just cut out too!

Step 3: Assemble the Body

Screw the cap into the hole you just made. It should fit snug (if not use a hot glue gun).

Next break the pour spout off (or cut it out). The spout plastic is pretty stiff and by pulling it down the spout will snap off (Flying debris alert!).

Next press the Circle you cut out of the side into the spout. If you did this right you wont need glue here either.

Step 4: Optional Paint Job

Depending on the bottle you have you might want to just paint over the label (Like the green saw at the begining of this Instructable) Or you might want to paint the whole thing like I did here.

Step 5: Cut Out the Blade.

OK here's another option. I'm using some old wall paneling for the blade BUT you can also use cardboard or any other rigid thin material. As a replacement for my real Chainsaw blade I used two pieces of wall paneling that sandwiched a piece of rubbery foam that was cut to look like giant saw teeth . . . yeah it was scary.

After you cut it out paint it as you so desire (make sure you use the taper on the one end, this will make it fit snugly into the bottle).

Since it will be dark out I just quickly painted the saw teeth onto the blade.

Step 6: Final Assembly.

Ok now take your painted bottle and cut a slit in the bottom along the Right side the width of the blade (as shown).

Now with the taper on the blade towards the top, push the blade into the bottle keeping it close to the right side. The taper (wich is just a small angle) should fit the Bottle's taper and hold the blade snug.

Use the two wood screws to secure the blade to the bottle.

Splatter some red paint on the blade for some gore and Pfft! You are Done!

You can add things too! Like a piece of rubber hose or a metal pipe bent in a U shape to mount as the front handle. Or you could put a motor inside it with a noise maker or rattle and turn it on for el-cheapo sound effects.

Great for Static props or little kids! Enjoy!
-Calilech