A Poor Man's Pannier

One of the keys to surviving hot weather on a bike is to get as much wind on your skin as possible. Because I carry a laptop in my pack-pack to and from school, so getting my bag off my back is an important part of managing the heat. I like the idea of mounting a pannier that I could stick my bag into, but they can be kind of pricey. Decent ones typically run $50-$100. I may have mentioned the cash-flow situation with graduate school before, but especially in my case, minimizing expenses is a high priority. 

That's not to say I want to go cheap, but I definitely don't want to spend unnecessarily, so I thought about other solutions. As a matter of fact, on first returning to school, I purchased a cheap back-pack from eBay that looked like it would be a good deal, but it fell apart half-way through my first semester. I replaced it with a very well-built and only slightly more expensive ($50) Super Deluxe Book Pack from L. L. Bean. It turns out this pack has a very strong handle on the top that turns out to be very useful for attaching it to my bike.I rummaged around and found that the rack that holds my bicycle baby-carrier was removable, and I had a few bungee straps. I installed the bike rack, and then, using the two S-hooks from a rubber bungee-strap, I secured the pack handle to the top of the bike rack, as shown in the photo. Then I used two more bungee straps: one to sling under the bottom of the bag to help take some of the strain off the handle. 
You can see it as the brown/yellow cord in the following photos. The other bungee strap wraps around the outside of the pack to hold it against the side of the rack so it doesn't move around while I'm riding. In order to make sure the shoulder straps don't get caught in the spokes, I cinch them tight and tie the loose ends around the padded part of the straps. This arrangement has worked really well for me this summer so far. The cost was zero, the improvement in comfort was substantial.Last of all, let me make one more plug for L. L. Bean. Their products are really focused on the end-user, and I don't get the feeling that any corners were cut in design or production. And you just have to love the sign they post in their stores and on the web: