By now, you've seen all the articles with tips about making/borrowing/repurposing costumes to save money. I'm not going to waste your time with that. I'm going to share some tips about Halloween that you might not have expected.
1. Buy Halloween socks when they go on sale. In the days/weeks after Halloween, they can go down to as little as a few cents per pair (I spent 12 cents on a pair at Wal-Mart last year). They often come in dark colors, particularly black. This is VERY useful for kids. We bought a ton of them last year and our kids make sure to wear those when we go to indoor play structures. Those places often get their socks very dirty, but with black, no worry about stains.
2. Stock up on Halloween goodies for birthday party goody bags. Last year, we bought those tiny packs of crayons and some glow necklaces half price after Halloween. If we had waited, we could have gotten them even cheaper when they went down to 75% off. We gave them out in goody bags for our son's birthday party. Packs of pencils are particularly useful for this. You can sometimes find a pack of 10+ pencils for a quarter once they go all the way down. If you don't want the Halloween designs, have stickers available at the party and make decorating the pencils one of the crafts/activities.
3. Some Halloween shirts work year-round. I see Wal-Mart has some super cute "costume" shirts this year. They're things like rock star, pirate, zombie, etc. These are cute year round. Some t-shirts are very definitely Halloween, but if you don't mind, you can buy them on sale (they often go down to $1 each and even less) to use throughout the year. Some can be used at other times without being obviously dated. My son had some very "Punk rock" ones that just featured skulls and crossbones. They were Halloween sale finds, but he wore them all the time and lots of people told us how much they liked them.
4. Those color hair sprays are a quick and cheap way to prevent the, "I'm booooooooored," chorus. You can grab them cheap after Halloween. Our homeschool group brings tons of these to summer parties to let the kids go wild. I advise parental intervention and I will tell you that they can stain the skin, but if you're stuck inside on a cold afternoon, you could always head outside with a can of hair color and a towel to cover the kid's clothes and come in with super cute pink hair.
5. Once costumes are dirt cheap, grab some of the basics to use in the future. Black robes are always useful. Wings can be used in a number of costumes. We have a box full of them and I can't tell you how much use we've gotten from them. Capes work with a variety of costumes. Stay away from the trendy costumes (no Hannah Montana wigs or Borat bathing suits), but grab some basics if you can. That gives you the ability to throw together a costume next year cheaply.
6. Throw a Halloween-themed party at another time of the year. My son has decided he wants such a theme for his birthday party in the winter because he wants an excuse to dress up. Fine by me. I'll grab a punch of Halloween-themed party supplies when they go on sale and save myself a ton. This is useful for lots of different holidays. I buy Valentine's Day goody bags/party goods/trinkets to use for my twins' birthday party every year. This past year, I bought those huge packs of lip gloss/nail polish for a deep discount after Xmas, opened the package and split them up in goody bags. We got 25 lip glosses/nail polish bottles for $2 total.
What do you think? Will any of these work for you? What tips do you have to add?