I have found a relatively cheap fermenter if you are trying to keep brewing on the cheap side. There are around $10.50 where I live(southwest TN), but in some areas I believe they are cheaper. It holds around 6.8 gallons, but it claims to hold 7. It is the color blue, but I can attest that there is no plastic flavor etc. as some claim. It is #2 HPDE plastic. It is somewhat difficult to move, but it has a handle on it which helps.
Here is a picture of it...
It can be found in the hunting/fishing section of Walmart(where all of the guns and fishing lines are located). I have been in about 3 walmarts and it is in all of them.
Someone had already mentioned it, but they never said how the beer turned out.
To turn it into a fermenter I capped the large white top and took off the air flow valve cap. Then I simply poked a few holes in the top of a balloon with a needle and put the balloon over the small hole with a rubber band around it.
The beer tastes fine and if you are looking to brew cheaply these work very well.