I agree with Kristan here. CD's are way better than tapes for demo purposes these days. It's possible to make them for so much less money. When I was younger (like 2 years ago actually) my band's made demo tapes. We sold them for two dollars and pretty much were lucky to break even, which I mean for demos that's not bad. Then we made a CD demo, because we did the math and if we sold those for $2 we could make our money back, plus a bit extra. This is of course figuring in the cost of recording the tape at a studio and all. But yeah, I guarentee you can do CD's cheeper, and if you don't have a burner, I can bet you that you know someone who does.
Good story about demos.....
We made a demo at our house when we were just barely together. We did all the mic placement and just recorded live to a tape deck through a mixer. I guess you can image that it sounded like crap. Anyway, we managed to sell 96 of those tapes for $2 each. So then we had the money to go to a real studio with all the money that we made. When it came time to pay the guy that ran the studio, we whipped out over 100 dollar bills, (126 I believe) and started making stacks of ten. You could tell he was kinda pissed, but he did see the humor in it all. The next time we came in he told me when I was on the phone with him making the appointment that we had to pay with 20 dollar bills. I miss those days.