I had a very hard time finding swords for a show that I did, and I wanted to use metal because I wanted them to sound real when the actors banged the swords together. I am not sure where to get cheap ones, but I do want to forewarn that you need to be careful what you do get. We found these swords at an antique store that were perfect for our show. Within a week of getting them they all broke. We didn't realize they were ornamental (decoration) swords that someone had cut out of steel. We had some where the blades broke in half and others that broke at the handle. And our actors weren't even full force swinging them. In case you have never used a sword before, you want to also make sure they are NOT sharpened and you should try to find a rounded tip. I have several swords that even though they are not sharpened, they have a point on the end that can still stab someone and injure them severely. Another is your actors. We have a mix of adults and youth and even after 6 months of rehearsals, people still continued to walk around with their swords pointed straight out - one of our actors stopped suddenly and the guy behind him almost stabbed him in the back. Luckily he had 3 layers of costumes on! We ended up getting rid of the real swords and went to a costume / prop store and bought plastic swords that we spray painted with a Metallic Silver paint and then sprayed them with a clear gloss to try and make them look more like metal.

I  have made wooden swords 

Watching "Robin Hood" with Errol Flynn, and during the huge fight scene the swords are going "click click" as they strike each other. I assume this was before gaffers and sound effects, so whatever they're using in the movie isn't real steel either.

Check out TrueSwords.com. They sell training weapons, but don't know how sturdy they might be. Pirate cutlasses are only $8.00! You won't find much cheaper than that.
http://www.trueswords.com/pirate-cutlass-wooden-sword-replica-p-2876.html