I recently discovered that the kindle store from amazon sells trumpet music. It costs a lot less than buying the paper version and is available for download immediately. So if you own a kindle or Ipad/Iphone with a kindle app (free from the app store), check it out!
Obviously this does make it slightly harder to read the music as it is smaller and you are unable to annotate, but I think it is perfect if you want to 'try before you buy'. You are also able to download a sample before buying which will give you the first page to look at, before you part with your cash.