Audible offers a $10 Audible Credit for free via coupon code "BUDGET2015". That ties our mention from last week as the best free credit deal we've seen. (We've seen a $10 credit several times before but only for new Audible members; this one is for everyone.) It's valid only for audio content; it can't be used for purchasing membership or gift cards. The credit expires 60 days after redemption.