Although the initial batch of freemium outings mainly offered a FarmVille-esque experience, a greater range of genres have now adapted to the free-to-play model.
This list steers clear of the aforementioned FarmVille and similar agricultural affairs, instead focusing on racers, shoot-'em-ups, and card games.
You can, however, check out Pocket Gamer's top 10 best iPhone farm games, for a rundown of the best grow-'em-ups the App Store has to offer.
Read on for ten of the best freemium games for your iPhone, iPad, or iPod touch.
Z2Live's aerial combat title MetalStorm: Online places you in the cockpit of dozens of fighters, as you dogfight, barrel roll, and engage enemy planes.
You can compete for superiority with players around the world over both 3G and wi-fi networks, or enter Survival mode with a buddy and encounter wave after wave of foes.
Aircraft customisation, Game Center leaderboards and achievements, and gyroscope controls are all on hand for Top Gun wannabes.
Download MetalStorm: Online (Universal)
GT Racing: Motor Academy Free +
Gameloft's fast-paced racer tasks you with passing driving exams, winning races, unlocking cars, and lining your pockets with cash.
GT Racing: Motor Academy Free + gives you a handful of events and cars from the off, but you can purchase more with packs of credits and XP. These can, of course, either be earned or bought through in-app purchases.
You can take the game's 107 licensed cars - ranging from the Nissan GT-R to the sleek Audi R8 - through a Career mode, or jump into local and online multiplayer for up to six people.
Download GT Racing: Motor Academy Free +
Download GT Racing: Motor Academy Free + HD
If you think you're a top-notch sharpshooter, or you have a keen eye for a bullseye, you can prove it in Overkill.
Your job is to use the game's selection of weapons to shoot and kill a selection of enemies that pop-up around five locations.
Using the money you earn from wiping out your opponents, you can upgrade and customise your range of weapons with improved scopes, stocks, magazines, and more.
You can fill your virtual mantelpiece with over 84 Game Center achievements, and blast your way up nine different leaderboards.
Download Overkill (Universal)
Tiny Tower, Nimblebit's latest foray into freemium gaming, charges you with constructing a busy, profitable tower building.
You'll build apartments, shops, and clubs, give pixelated bitizens a new home, employ workers, and stock your stores with a range of goodies.
Game Center is once again present to handle all of your competitive needs.
Download Tiny Tower (Universal)
Check out Pocket Gamer's beginners' guide to Tiny Tower
Sunshine Cruise Lines
Unlike IUGO's previous freemium hit Lil' Pirates, Sunshine Cruise Lines takes place on calmer oceans.
You, the owner of a cruise ship, have to equip it with bedrooms, spas, gyms, restaurants, and range of other time-killing attractions for your passengers to enjoy.
You sail from country to country and from port to port, collecting coins, earning experience, grabbing postcards, and unlocking Game Center achievements along the way.
You'll also be tasked with picking up special VIPs, employing new staff, and making sure each trip on your prestigious ship goes swimmingly.
Download Sunshine Cruise Lines (Universal)
Gun Bros is your chance to take control of a big burly man, armed to the teeth with state of the art weaponry and a penchant for destruction.
When you're tired of battling side by side with a computer-controlled buddy you can jump into the game's new multiplayer mode and team-up in real-time with a shooter of your choosing.
You even have the ability to scream orders with built-in voice chat.
Bro-op challenges, Game Center integration, and daily rewards are also present.
Download Gun Bros (Universal)
Pocket Frogs is a unique game that tasks you with collecting, breeding, and trading over 15,000 different species of frog, both on and offline.
You can explore ponds to earn coins and decorative items, give your frogs' habitats a well-deserved makeover, and send your little amphibians off to your friends. It's like football stickers, but with frogs.
If you're an active user of Apple's Game Center you can unlock over 60 achievements for collecting specific rare frogs, including a species that looks like popular Pokemon, Pikachu.
Download Pocket Frogs
Space City is the latest offering in a long line of freemium titles from publisher Glu, and it's also one of the best.
Your job is to create a bustling metropolis on an outer space asteroid in order to attract various varieties of alien tourists.
You have over 60 unique buildings to accomplish your task, such as diners, cinemas, stadiums, and museums - each gifting you a steady income of credits (cash) and experience.
And when you're done with building you can visit a friend's asteroid through Facebook and Game Center - with the latter also offering achievements.
Download Space City (Universal)
Magic the Gathering-esque collectible card game Shadow Era allows you to choose a starter deck and battle it out against computer opponents and other players.
You can currently add over 100 cards to your arsenal, chat with your buddies as you destroy their cards, and work your way up leaderboards - providing you have the required skills.
You can play both offline and online, with your progress accessible on your iPhone, iPad, or even in your web browser.
Download Shadow Era (Universal)
Hexage's strategy RPG Robotek HD follows a robot uprising and the subsequent battle to retrieve humanity from the brink of destruction.
You're tasked with destroying robots with lasers, electricity, microwaves, and whatever else you can lay your hands on across 200 levels of action.
As you battle, you'll be rewarded based on your skills, with nine customisable slots giving you the option to play as you please.
You can challenge and compete against your Facebook friends when your tired of destroying wave after wave of computer controlled foes.
Download Robotek HD (Universal)