A bond repays its notional face value (plus interest sometimes), not the original purchase price. Do not assume the the price you pay for a bond is its face value.
Sometimes a law or a regulation (pretty useless, in my humble opinion:) does require that a bond newly issued in primary market be sold at exactly 100% par price (face value). Then the coupon needs to be tweaked to price the bond exactly to par under the current market conditions and bond invesntor demand.
If the bond pays no coupon (zero-coupon bonds such as T-bills) and the interest rates are positive then of course no one would willingly buy such a bond at face value. It has to be sold at a discount.
Of course once the bond is being bought and sold in secondary market, it is unlikely that it is traded exactly at par.
If regulations don't require the new bond to be sold exactly at par, then the originators will often set the coupon so the price is expected to be close to par, for convenience, but then price at whatever the bond investors will pay - perhaps some people are willing to pay 101? Alternatively sometimes the originators will "tap" an existing issue - issue more bond with the same maturity, coupon, and other terms and conditions as an existing bond, selling at whatever price the market dictates.