TubeNet

You can find an excerpt book here, but I am not sure that is what you are looking for:

http://www.cimarronmusic.com/search.cfm?id=188

IF you are just looking to sightread "stuff", I would suggest etude books from other instruments. Trumpet, Horn, etc.

If you have a music notation program like Finale or Sibelius you can open any midi file you can download. Lots of sites protect against this by coding it to look awkward and terrible, but if you are just looking for sight reading, try downloading midi's of your favorite video game music and read all the lines.

I did this a lot in high school because if you play with the playback it forces you to keep going and you can teach yourself to transpose if you want. If you don't, just slap a bass clef on the line, make sure the score is in concert pitch (transposition off), and lower the part until it is in a good octave, just make sure you keep the accidentals true to a key.

Granted, you most likely will never play any of that music, but I think it's a great tool to work on sight reading if you are short on money or just don't feel like shelling it out, plus there's the option of playback so you can force yourself to keep going and keep tempo a little easier.

http://www.bandmusicpdf.org/

This one is great for old marches.