How costly is it to fix a transmission leak?

FIND THE SOURCE OF THE LEAK AND CONCENTRATE ON CATCHING THE FLUID COMING OUT IN A CONTAINER FOR REUSE. MINE LEAKED AROUND THE HYDRAULIC LINES-GET A SET OF LINE WRENCHES OFF SOMEBODY OR BUY THEM AND TIGHTEN BOTH LINES ON THE TRANNY AND ON THE RADIATOR-BE CAREFUL AND TAKE YOUR TIME-SNUG IS OK. DON'T WANT TO BUST KNUCKLES ON THE HOLIDAY OR THOSE LINES. IF YOU FIND THEM NOT GETTING TIGHT-THEY ARE STRIPPED AND WILL NEED REPLACED ASAP. MAKE SURE YOU DON'T HAVE ANY FLUID ON THE MUFFLER OR PIPES-A VEHICLE FIRE IS NOT PRETTY TO YOU OR OTHER MOTORISTS,ESPECIALLY AT THE GAS PUMPS ! GOOD LUCK TO YOU MY FRIEND !