If Thomas hasn't depressed you enough, be prepared for quotes which will probably be way beyond your means, as an ATCO I was quoted around £300 per year for a one off payment of £30K.
I assume that you are looking for cover to take into account possible loss of the bond payment, I thought that you could take out cover via CTC for this? As a mere sprog embarking on your first leap into aviation, I don't think you'll find anything cheaper than their cover, and almost certainly, it's unlikely that you'd get cover for the full amount of the bond for a realistic price.
All the best with the course though...