If you're looking for a new game to try out with your friends, but don't want to break your budget with a huge initial investment, these games are for you. I have most of them in my personal game bag, so I can personally recommend them, and they are quick to pick up and easy on your bank account.
This game is just what it sounds like: you play a hungry zombie. You have to find more brains than your fellow zombies, all the while avoiding being shotgunned by the tasty humans. It's quick to set up (set-up includes: opening dice tin, picking three dice, rolling said dice) and quick to play.
Available on Amazon: Zombie Dice
This game (put out by Lars and Sohmer over at Least I Could Do) is quick to pick up: you and the other players run the cast of LICD trying to pick up women at the local watering hole. It's a bit irreverent and not exactly child-friendly, but it's worth picking up!
Evil Baby Orphanage is everything it sounds like and more. You play as a Time Nanny, kidnapping evil babies from the Time Stream and rehabilitating them to be... not so evil. Babies have various problem-causing abilities (like biting), but can be placated with toys. It needs three or more players, but it's quick, fun and has a great price point.
It's available here: Evil Baby Orphanage
Another from the repertoire of Steve Jackson Games, Cthulhu Dice pits acolytes against each other in a pocket-sized dice game. Each player starts with three sanity - roll the dice and see if you can keep it. Last sane person wins!
Available on Amazon: Cthulhu Dice
When I saw this at PAX East, I knew I had to have it. It's definitely a game for larger groups, but it has a simple, streamlined rule set and you can be up and running within minutes! Great for parties and to play while waiting for that last player to show up on RPG night.
Available on Amazon: We Didn't Playtest This Either Card Game
AEG has a history of putting out quality games, and Love Letter is no different. Play a suitor vying for the hand of the princess, and woo her by getting a letter in her hands, while preventing other players from doing the same!
Available on Amazon: AEG Love Letter
A game in the same vein as Zombie Dice - you are the mighty hunter, seeking out dinosaurs while avoiding their massive, body-crushing feet! The rules are short and to the point, and even new players can get into the game minutes after purchase (or, if you buy it on Amazon, minutes after receiving it).
Speaking of Amazon... you can buy it here: Dino Hunt Dice
The rules of Fluxx depend on what cards are in play - each has its own custom tweak, so the game area is constantly changing as you and your opponents play. Because of its unique style, it is easy to pick up (just make sure to read your cards when you get them!) and can be a great game for newbies and veterans alike!
It's available on Amazon: Fluxx
This game takes longer to set up and play than the others that have been included (and it's part of why this list is $25 or less instead of $20 or less), but it is worth it. Anima is a fantastic focus for an entire game night, as you play an adventuring party trying to stop Omega from destroying the world. It is complex, with a rich rules set and plenty of opportunities to help (or backstab!) your fellow players.
It's available on Fantasy Flight Games' store here.
If you're looking for long-lasting fun with the tongue-in-cheek humor that Steve Jackson Games are famous for, look no further. In Munchkin, you take on the role of an adventurer, killing monsters, exploring dungeons and trying to score fat loot before anyone else does! It's a favorite at my gaming table, and has a number of expansion packs to keep the fun rolling week after week.
It's available on Amazon: Munchkin