stock pot

Items includes Stainless steel stockpot with tap hop and strainer - 15ltr Stainless steel stockpot - 15ltr Mashing and Sparging Bag Small Plastic Trial Jar Hydrometer with Case Steriliser 250g Mixing Spoon/Paddle 10lts Bucket with Lid, Grommet, Airlock and Tap 10 Litre Bucket with Lid and Tap...

I am looking to get into brewing some beer after trying my hand at wine. I have 2 questions regarding brew pots. First, if I am making a 5 gallon batch, how big of brew pot will I need? Secondly, where can I get a good quality one at a lower price? All help is greatly appreciated...