Pirates.It's easy to sut a pair of black pants to ribbons. Make belts, head bands, and sashes with strips of cloth. An eyepatch can be done easily. You can make a hook out of cardboard and aluminum foil. Hobos are easy, cause you can use a stick and bandana.
Hobos, Use some old clothes and tear some holes, then wash them so they fray get an old hat and smudge it all with dark facial powder for "dirt". Use eyeliner and draw beard stubble.
Zombies... same principal, tear up clothes, go without a shoe.. cornstarch blood recipes are easy to find on the internet.