Amazon Cloud Drive, the online retailer’s version of iTunes, is striking back at Google and Apple with unlimited music storage and a web app for iPad.

The changes affect all new purchases of Cloud Drive storage plans. If a user spends $20 for a year’s worth of storage, he or she will still get 20 GB of space. However, MP3s and AAC files no longer count against the limit. This applies to all Cloud Drive plans, although Amazon says the deal is only available “for a limited time.” Non-paying users of the service will still get 5 GB of space for free, according to Mashable.

In addition, Amazon has also announced that all MP3s purchased through Amazon will be stored for free as well.

The move is clearly a shot across Google and Apple’s bows. Google Music has a limit of 20,000 songs, while Amazon has no limit. Apple’s iCloud doesn’t offer uploads, but instead has an iTunes Match feature that finds a high-quality copy of your music library for $25 a year.

In addition to unlimited music storage in the cloud, Amazon also announced that it has optimized its web-based Cloud Player for the iPad, allowing users to access their music library from their Apple tablets. It’s the next best thing to an official Amazon Cloud Player app.