Ok, here's my recipe for ya!
Depending on your size, if your smaller, you can prob buy a 2 piece Jango and modify it. $30
Jango 2 piece
Then head to Wal-Mart and pick up a few things. First, buy an off brand Dremel or rotary tool. It will be very valuable for you work in the costume world. Make sure it comes with sanding drums and a cutting bit. Likely a little less than $30. Then pick up a pack of sand paper of a fine grain and some steel wool ($5). Grab a hot glue gun and a pack of sticks ($5), a small can of Bondo ($8), a fiberglassing kit ($12), maybe some JB Weld ($4) and whatever paints you want for your Mando. A Lowes has a cheaper off brand called Valspar which is really good. Just be sure to grab a can of flat coat and silver for sure. Go to the section where you find window screen and grab a pack of foam ($3). It's in a long thick strip folded on itself. You will be using that for padding in your gaunts and helmet. Look here to see if there are any cheap laceless boots if you don't already have a pair at home. Grab a pair of mechanics or yard working gloves ($5) as they make great Mando gloves.
Try to hit up a military surplus store and buy a used coverall/flightsuit. I got mine for $12 and they had tons in different colors. You can always buy some Rit dye to change its color ($2 a box). Also ask for a neck gaitor ($5). They are simple neoprene or polypropylene sleeves you put on over your neck. Makes for a simple and easy neck seal. Usually in brown or black. Find a Salvation Army or whatever for nice belts to add as accessories. Maybe you can find a vest or slightly padded shirt you can cut the sleeves off of to make your vest. If not, try to find someone with a sewing machine. Ask around. If you buy 3 years of twill ($10) and some interfacing ($3) along with some muslin for lining ($3), a vest can be easily made. Look for window tinting as well and pick up some. Lastly try to find a safety store that sells fire extinguishers. You can find face shields her for roughly $4 as you will need to replace the visor in your Jango.
Next, look around for sign shops, plastic stores or architectural offices. Ask for Sintra / foam PVC. If you cannot find it, here are two resources:
TAP Plastic
Ebay Seller
If you want a Boba style (chest, knees, back and gaunts), you can do this with a 4x4 sheet. Buy the 3mm or 1/8 inch. You can cut it with a simple box cutter you can get from Wal-Mart or Lowes for $7. If you want a Jango, go with a full sheet - 4x8. Hopefully you can find this locally. I buy 4x8 sheets from TAP down the street and it's $39.50. Shipping will eat you up. You can always use a cape instead of a backplate, saving you alot of plastic.
Go to the Boba or Jango section here and download all the WOF templates for your size. Print and trace it on your plastic and cut. Be sure to put the cut paper on your chest to make sure it is the right size. If you are brave, you can pick up some For Sale signs at Walmart and make a helmet and real gaunts from scratch using WOF's templates. Just be patient and realize it's going to take a few attempts.
For your belt look up the Batninja tutorial. Basically find a hobby shop that does R/C airplanes and get a 3x3x12 block of balsa wood ($5) and a miter box with saw ($10) along with a half yard of good pleather or leather from a fabric store ($6). If you want true Boba style and get a girth belt, look here:
Girth Belt
Buy some latex wood stain from Lowes ($8) and give it a bath in it. In a day it will dry and you'll have a great girth. For attaching all your stuff, buy a box of industial stickyback velcro from Wal Mart ($18) and some sew on ($4 a yard). Pick up some webbing and elastic by the yard and maybe two buckles. I also recommend ultra flat black spray paint for dusting all your soft and hard stuff to weather it. Possibly the cheap Apple Barrel paints in Wal-Mart too in black, tan, grey and those colors to weather.
Finally, go home and READ, READ, READ this forum and also the
www.mandalorianmercs.com. Find the local group/clan in your hometown and go to their armor parties. If you need more advice, feel free to PM me.