There are loads of bands on the internet offering their music as free downloads on their websites. Either as zips or direct mp3 downloads. What ways are there for iphone/ipad users to get the music playable via itunes without taking the mac/pc detour and without jailbreacking?
iCab Mobile -browser here downloads the files to its own dir in the app and then you can open things in external program let say DropBox. It has some problems with some formats but there is a hack: you can zip things and then it will work for sure. It works at least with PDFs, MP3 and ZIPs.
Below you can find a proof, I used the soundtracks here. And I did not use iTunes -- only iPad, free of iTunes jail :D
When "previewing" an MP3 in Safari or in Mail on an iPad, in the past several versions of IOS, you have the "Open In" option to put the file in any installed app that can accept files. Many such apps can play MP3s. However, "Music" (formerly known as iTunes) will not be on the list.
Nothing against GoodReader or iCab, but neither of them is mandatory.