If you are skint and not too fussed about the type of tyre try visiting your local bike shop asking if they have any take offs, or part useds.
Take offs are what come fitted as standard and people get they to change when buying a bike.
I occasionally go out with local youth group cycling session, they get given part worns and pay something like a fiver when getting take offs.
All that said, where are you in the country and what size tyre?
While we are comparing tales of woe I had a bead fail on a MTB tyre once, inner tube came out and wrapped itself around the forks. All a bit exciting at 30mph+ in traffic on a steep decent.
Probably caused by miles of rolling along with the tyre flat after a puncture.