If you’re hoping for a Kindle or iPod Touch this holiday season, it pays to think ahead. Which apps will you buy? For $10 you could get a half-dozen new games. But with thousands of choices at the App Store, Amazon and Google Play, how do you know which ones are fun and which are a waste of a dollar? KidsPost tried out new apps for 7-to-12-year-olds — games, puzzles, arts and crafts, and even a few your parents would call educational — and picked some to entertain you over the holidays. The paid apps are worth every penny, and a few won’t cost you a single cent.

Angry Birds Star Wars

The birds are back, and they’ve got the Force on their side. Angry Birds Star Wars dresses the birds as Luke Skywalker, Obi-Wan Kenobi and other characters, and gives them extra powers to knock down those pigs, which are now Pigtroopers. Luke has an obstacle-slicing light saber, Obi-Wan has the Force, and Han Solo has a blaster. The game opens on the planet Tatooine, moves into space — where you have to deal with zero gravity — and then to the Death Star, which has the face of a pig. If you fail a level, a Darth Vader pig appears and laughs, or oinks, at you. A free bonus level features R2-D2 armed with a tractor beam and a C-3PO that falls apart. Gamemaker Rovio promises a free update featuring the snowy Hoth planet. Will the pigs strike back?

Rovio. Android: free; ad-free version for Android, iPod Touch, iPhone, iPad: 99 cents; HD version for iPad, Kindle and Nook: $2.99. In-app purchase of second bonus level: $1.99.

Where’s My Perry?

Perry the Platypus from Disney’s “Phineas and Ferb” has a spin-off of the popular “Where’s My Water?” app. Perry, or Agent P, needs to get to his underground base to uncover the latest schemes of evil Dr. Doofenshmirtz. But the water that fuels his transport tube has been blocked by gates and lasers that change water to steam or ice. Players have to find a path for the water and try to collect bonus gnomes along the way. The free version has one mission with a dozen levels. Paid versions include four missions with 20 levels each.

Disney. Android, iPod Touch, iPhone, iPad: free; ad-free version that includes more levels: 99 cents; Nook: $1.99.

Meet the Insects: Forest Edition

December isn’t prime time for nature walks. But if you love bugs, you don’t have to wait until spring to see butterflies, cicadas and stink bugs, thanks to this app. Check out a video of two male Japanese beetles fighting over a female or a brown cicada turning into an adult. You can read about insects’ life cycles, their colors and patterns and their habits. The app features no games, but there are two types of quizzes to test your knowledge. An observation journal for when the weather cooperates helps you investigate what insects are in your back yard or neighborhood park. You can even upload pictures to your virtual journal. Developer NC Soft, which worked on this app with the National Science Museum in South Korea, promises that more insects are on the way.

NC Soft. iPad only: $3.99.

Toca Tailor

If you’re particular about what you wear and enjoy mixing and matching clothes, Toca Tailor is a good fit for you. Four characters — a boy, a girl and two animals — come simply dressed in a shirt and pants. A slide of the finger turns the pants into shorts. A tap changes the style to puffy or cutoffs or a miniskirt. Tap on the box with the thread to change patterns — and you can pick more than one. (How about shorts that have polka dots on one leg and leopard spots on the other?) You can also add pockets, buttons and zippers to your colorful creations. Complete your outfit with hats, scarves, shoes and other items from an accessories box. When you’re done, click on the mountain symbol to take a picture of your model in whatever setting you choose. Photos will save to your device’s camera roll so you can e-mail them to friends.

Toca Boca. iPod Touch, iPhone, iPad. $2.99.

Half Team

Collaborating, or working together, isn’t common among painters. It’s hard to imagine Pablo Picasso saying to his friend Henri Matisse, “I’ll do the left side of the canvas, and you do the right.” But that’s the idea of the Half Team app. You can use e-mail to work with a drawing partner far away or use “pass and play” to draw with someone in the same room. Choose the top or bottom of the drawing space, and then choose your tool and color. You can mix thick and thin lines and change colors. You can also add a label or voice recording. You mark how wide your drawing is, then let your friend take over. He starts with a blank half-sheet, and both of you see the finished product when your friend is done. The results can be very funny: a brown bear with chicken legs or maybe a house with flowers coming out of the roof.

Clustered Apps. iPod Touch, iPhone, iPad: $1.99.

Aliens Abducted

Which flag is the one with the red maple leaf in the center? If you answered “Canada,” then you’re up for the challenge of Aliens Abducted. Three aliens — Moe, Barry and Marvin — have been taken from their planets and sent to Earth. They need your help to learn which countries are where. Look at the map and match one of three flags to the highlighted country. The clock is ticking, and every wrong answer means one of the aliens gets zapped. (You can use the “library” to review where countries rest on the map along with each nation’s capital and population.) With enough correct answers, you can unlock Escape Mode, where you help Moe defeat evil robots while running along a platform collecting coins. This part requires no mastery of geography; it’s just a fun detour.

Bilu Games. iPod Touch, iPhone, iPad: free; add more levels with 99-cent version, which is free for a limited time.

The 39 Clues: Vesper Hunt

You don’t have to be a fan of “The 39 Clues” book series to enjoy jumping into the world of spies and evil plots. You’re part of the Cahill family, and the archenemy Vesper is always up to no good. You receive an assignment that will require you to solve puzzles in order to unlock clues about Vesper’s latest plot. Is your suspect male or female? Does he always wear a hat? Does she have an interest in knitting? Use the clues to narrow your suspects, and the command center will tell you if you’re on the right track. If you guess wrong, the Cahill database may provide a clue or let you send in a backup agent for help. If you find your suspect, you earn a medal and, of course, save the world.

Scholastic. iPod Touch, iPhone, iPad: free.

Word Winder

If you’re looking for a more challenging kind of word-search puzzle, this app passes the test. In the app’s Finder game, you are given a series of clues about the hidden words. (For example, a Pacific Northwest state that has six letters. Did you guess “Oregon”?) Once you think you know the word, look for it on the board. The twist is that words aren’t usually in a straight line; to make one word, you might zig-zag all around the board. (See “publication” in the example above.) There’s a dictionary and a hint button that will reveal a few letters in the puzzle. As many as three people can play at once, and there are “Speed” versions. If Mom and Dad think this is just for kids, have them try the “Challenge” game.

Word Winder. iPad only: free for three games and one bonus level. In-app purchases of 99 cents to $1.99 unlock additional games.

— Christina Barron