
If you can find a livestock market, they sometimes sell produce too. At melton market, shot/ferreted/lamped (?) rabbits are auctioned in pairs and usually go for about £3. Hares are sold separately and can go to £6/8 each. Bare in mind however, you will need to skin, behead and portion them yourself. The rabbits are gutted but hares aren't.
Last year we bought an entire chinese water deer carcass (head off and gutted), skinned it, kept a leg for ourselves and let the dogs go at it in the garden. £32 for 14.2kgs and 4 very happy shepherds.