Shady Lamps you are on the right track! Second hand stores are a great place to make a tramp costume. Here are a few things to remember,
First, a tramp is not a fashion plate. Look for an outdated suit, preferably a dark coloured one. My Coat is a brown Tweedish type and is a suit coat, and is too large for me. Because it is loose it gives me freedom of movement and makes me look smaller than I am.It has many rips in it. some I have sewn up with thread, some with embroidery thread, some with Buthchers twine.
others, I have left torn andsome are held with safey pins. I have many patches on my costume, various shapes and colors, some overlap and some don't. All of the patches are cut from various swatches of different fabrics. A tramp would patch his clothing with whatever was availible for him to use. and would likely not hem the edges and would certainly not have put them on with a sewing machine! Be creative, but think about it.
My pants are a dark Navy Blue and are big enough to hold two people. A good rule of thumb is ;if you don't need suspenders to hold up your pants, then they are too small 8O I hemmed them uo enough that I wouldn't catch my feet in them when I walk, and are treated like my coat.I even used an office stapler to hold a few areas together.For suspenders I use a pair of blue ones. A more authentic touch would be to use cotton rope through the belt loops.I prefer the clip on suspenders for ease of cleaning. I wear an old tattered blue cotton work shirt that is very faded looking And I use a very ratty burgundy tie, I use and old nasty looking spring clothespin for a tie clip. I have also seen a small mousetrap used.
A tramps clothing should never be dirty. There is a difference between looking like a tramp and looking derelict. Keep your costume clean and pressed. Don't put paint or grease on it. It is okay for your costume to be rags, but again. It should be clean.
Here are a couple of places that make tramp costumes. It will give you some ideas. To me a tramp should make his own costume. A real tramp would have done the same!
www.mooseburger.com
www.clowncostumes.com
I regards to a hat. The right hat will find you!