Putting together a game night with your friends is a rewarding experience. You get to sit around and share laughter and stories, all while enjoying some delicious food and a little healthy competition. Board games can be very expensive, though, and unless a piece is missing or broken, there's no reason a used game can't be as enjoyable as a brand new one.
Some of the best board games to buy are not actually board games at all (but we usually call them that because they're packaged in a box like a real board game) -- instead, they're party games like Pictionary or Cranium that can be played over and over with the same or different groups and yield entirely different results. Mad Gab and Boggle are also uproarious fun when played with enthusiastic friends, but for a quieter crowd, get a real board game like Monopoly or Clue.
If all you can find are decks of cards, buy them up! There is a plethora of excellent card games that four or more people can play, so even if you're expecting a large crowd, don't be fooled into thinking cards are only for small groups. Play a big game of Texas Hold 'Em, or Hearts, for some strategic games. Or, for something more fast-paced and competitive, try Nerts, a stacking game that can be comfortably played with up to eight players. (Rules are here: http://www.pagat.com/patience/nerts.html)
Feeling super ambitious? Make up your own games, using toys and other substitute playing pieces you find in the free or 10¢ box. Start out the evening by coming up with a set of rules, which you can then play out using the pieces as player chips, obstacles, board spaces, or whatever your creative minds can conjure up. Save the pieces in a box and write down the rules so you can play it again, or, if you didn't really enjoy it, scrap it and start over.
A super competitive group might have fun competing to win prizes, and garage sales are the perfect place to get gimmicky little items that can serve as the winner's bounty. A matching penguin salt and pepper shaker, a rusty charm bracelet, or a deflated football can be fought over as you and your friends battle on the board. The type of prize shouldn't matter if it's just a matter of pride and having fun.
A themed game night needs some decorations, which you can find at garage sales as well. Though you may not be in luck if you go out shopping with a theme in mind, allowing yourself to be inspired by what you find is a great way to pick up some cheap decorations.
Finally, you could add some spice to the night by trying out a new dish or snack prepared in a way you've never tried before. If you don't have the proper equipment to do so, you can always pick something up a yard sale for a few dollars. Who knows -- maybe you'll find it's a technique you really enjoy!
Just remember: there are some things money can't buy, but for everything else...there's garage sales! (Come visit GarageSaleCow.com for more great resources to help you navigate the wide world of yard saling!)