For 'cheap' is a pretty scary term. French Bulldogs are not low maintenance dogs. They are not even cheap upkeep. So in addition to the initial expense someone considering a bulldog should consider whether they can afford all the things after purchase in addition to the hefty sum of the initial purchase. There's stenotic nares, pallet repairs, cherry eye, entropian, demodex, allergies (a high quality food that meets their requirements is a must), other skin issues, hernias and eye injuries just to name a few and what if there's actually something WRONG with your pup. You will more than likely run into one or more of the above mentioned issues (and they are not covered under almost any circumstances) and there are many other things they are prone to. If someone wanting a French Bulldog isn't able to put out a ton of money initially but still thinks it's the breed for them they should look into the French Bulldog Rescue Network, French Bulldog rescue League, or the French Bulldog Village and see if there's a dog available who needs their help and is a good fit and be sure to do plenty of research. They're worth it if they're right for you.
