Cheapest pack or pannier...
 

...that can fit a few textbooks in it. Any suggestions?

yardsales. I got a pack that would fit a couple textbooks (if i needed to transport them :p) and two extra water bottles for 75 cents. Water resistant too with a velcro flap over the zipper. Yardsales are great.

Drop in at Canadian Tire ... you can find some pretty cheap ones there and they are reasonable quality. I wouldn't want to go on a long tour with them, but they'd probably be all right for hauling books back and forth to school.

I've got a set of Raliegh saddlebags, the kind that have an attatched bag that goes across the top of the rack. More than enough room for books! It cost about $20.00 last Christmas at Canadian Tire.

I zip-tied a military respirator bag to my rack for a few years.

A pair of milk crates and some heavy cable. Lash them like saddlebags and zip tie to the rack. Now you can carry school books, backpacks and groceries and have the street cred of recycled cr@p on your bike.

Here is a cheap set of panniers from Nashbar for $25.00. I bought a set for some short weekend touring. They aren't waterproof, but some plastic bags would do the trick.

http://www.nashbar.com/profile.cfm?c...eid=&pagename=

Lion, I took a look at that Nashbar - looks good. Are they big enough to fit textbooks?

How do they mount? From the picture, it looks they're floating behind the seat - not sure on what.

Also, do they block the rear reflector/blinkie.

PS Everyone else - thanks for the suggestions - if they're available online, please let me know.

Another idea is to hit the "Back To School" sales and get a pair of cheap backpacks. Just undo the straps and wrap 'em around your rack. You can either buckle them to each other, tie 'em or use those big safty pins, the ones you see sometimes on kilt style skirts.

I got a pair from Save-On last year that were only $4.99 Cdn each. They seem fairly waterproof - they've got a sort of inner coating - and they have a total of seven pockets each! The top closure is a drawstring/flap combo. They're pretty big, too.

Don't forget the Salvation Army, Value Village, Goodwill and MCC. I saw a set made by Supercycle that would probably work at Value Village last week for $6.99.

The bags at Nashbar hang over a rear rack, like saddle bags. They go on very easily, and are secured to the side rails of the rack with medal hooks attached to, pulled tight, canvas straps. They are about 11" X 11", and about 3-4" deep. Not huge, but I think they could hold a couple of text books. A rear reflector/blinkie mounts on the rear of the rack, or on the back of the seat. The bags have additional canvas straps on the top of the rack area to lash other things to the top of the rack.

Forgive me for being a newbie, but does that mean I need to purchase a rack also?

Yep