It's hard to find a good game with a small sum of money. Luckily there are a couple superb gems out there for your Nintendo Wii that shouldn't cost you much more than half the price of a normal Wii game. The other perk is that you can get these games new at the store and still get that bargain price. You wont need Ebay this time so check them out!
Endless Ocean

If you are a hardcore action gamer, then definitely avoid this game. Endless Ocean sets you in the role of a scuba diver who is searching for sea creatures and treasure in the Manaurai Sea. The game has a very relaxing feel to it and is great for people who just love the feeling of exploration.
No More Heroes

No More Heroes is a great blend of action and style. It has crazy, over-the-top but rewarding action that you just can't get enough of. The Wii remote just enhances the fun of the combat even more. This game is pretty much Endless Ocean's opposite.
Zack & Wiki: Quest for Barbaros' Treasure

Can you get past the title? Can you get past the kiddy characters and box art? Well if you can get past those, then you'll find one of the best original adventures you could possibly find for you Wii. It is a classic point-and-click adventure and uses the Wii remote in the best ways possible to find the many treasure chest set across the sea.
Okami

Speaking of adventures… this is a great one too. Okami Wii was a remake of the Playstation 2 version. You will go on an adventure as Amaterasu the wolf and during that adventure you can perform many spells using a Celestial Brush. The control enhancements on the Wii make this a good buy even if you have played the first one.
Resident Evil 4: Wii Edition

One of the best games to ever grace the Gamecube returns at a budget price with precision Wii controls. Resident Evil 4 takes place in Spain where a parasite has infected a local village. You must get to the bottom of it while saving the president's daughter and shooting down tons of crazy infected villagers.
Mercury Meltdown Revolution

Mercury Meltdown is probably the most budget priced game of them all. You'll find it for about 15 bucks these days. It is a puzzle game where you need to roll around a blob of mercury to get to its goal. It's kind of uninspired, but still amazingly fun for a 15 dollar game.
Geometry Wars: Galaxies

Geometry Wars didn't start on the Wii either, but it is more fun than using the Wii pointer. If you like style, space shooters, and getting high scores, then this game is definitely for you.
I really want to try out Zack & Wiki.