Currently audio files are included in Adobe Stock subscriptions. If you buy a subscription and don't use all of your quota before cancelling you will lose the unused quota. The annual subscription paid monthly is a 1 year commitment and can only be cancelled without a fee when the year is up. We also offer month-to-month subscriptions that can be cancelled at any time. If you prefer not to sign up for a subscription you can purchase credit packs, the smallest pack being 5 credits and the credits expire after 1 year. 1 credit can be used for any standard asset, which currently includes audio. Credits are roughly equivalent to $10 US. You an also use credits to license videos and premium assets.