Sure, you can buy swords in tons of places these days: malls, martial arts schools, internet suppliers, even Amazon.com! But most of those are crappy wall hangers that will fall apart under the stress of actual zombie combat. You might use an Asian World of Martial Arts special as a last ditch resort to take out a couple of walkers, but I wouldn't bet my life on a stainless steel 3-foot butter knife if I had to face any of the other Terrors of the Night.
No. Do some research. Go custom. Pay top dollar and demand commensurate quality in your melee weapons!
Custom shop Ollin Sword Design makes all kinds of swords, and all of them are ready to cut through the legions of darkness. But they go a step further and make a special Zombie Defense Collection of hard hitting large knives and short swords. They refer to them as machetes, but they look more like no-frills cutlasses to me. These things will chop through anything!
They aren't cheap, but they are sturdy, and with a little tender, loving care and maintenance, these short swords will protect you and your suceeding generations from things that go bump in the night.