Get an OLD HICKORY butcher knife and modify it.The edge can be convexed and has enough carbon content that it can spark on flint or quartzite rock.It might be a little more than ten dollars but its a "modern" version of a trade knife.They have gone up in price but the COLD STEEL Bushman is another bombproof blade.Cold steel often has a "threefer" deal on these....

BOATMAN
John