The board may purchase bonds for cancellation, using any available monies, at a price not exceeding the following:
1. If the bonds are redeemable at the time of purchase, the applicable redemption price plus accrued interest to the next interest payment date.
2. If the bonds are not redeemable at the time of purchase, the applicable redemption price on the first date after purchase on which the bonds become subject to redemption plus accrued interest to that date.