Use things you already have lying around the house:
1. Like gloves, which make easy moose antlers:
2. Make bat wings from an old umbrella:
3. A picture frame and some non-toxic paint can turn you into a work of art in minutes:
4. Or, if you're more into Pop Art than Impressionism:
5. Use paper towels to make a mummy costume:
If you want to be especially relevant, dress up as something from the news:
6. Like the giant eyeball:
7. The iPhone 5:
8. The Jesus fresco:
9. The Mars rover:
10. Or Paul Ryan:
11. ...A vampire!
Couple's costumes that won't make everybody hate you:
12. Bacon and egg:
13. Silent film stars:
14. Peanut butter and jelly:
15. Tom Hanks' character and Wilson the volleyball from "Castaway":
16. Play-doh:
17. Paint chips:
Group costumes are fun and low-stress (just make sure it still works even if one of your friends decides to leave the party):
18. With matching tracksuits and fake gold medals, you could be the US Olympic Women's Gymnastics Team:
19. Tetris:
20. Rocks, paper, and scissor:
21. M&Ms:
You know who absolutely loves Halloween (or at least doesn't have a firm enough grasp of the English language to communicate hatred)? Your baby!
22. Popcorn vendor:
23. Spider and web:
24. Bank robber:
25. The old man and the little boy from "Up":
26. But remember, just because you can DIY something doesn't mean you should. Like Snooki and Lorenzo:
27. Or these boobs:
And even if you're not into wearing a costume yourself, you can always dress up your pet: