I recently tried to find a 2L Erlenmeyer flask for doing Yeast Starters. Many of the flasks for sale in Ebay start at about £16 plus postage so not a cheap purchase. Well I did find a source where you can get them for £6 incl VAT. They do a complete range as they are sold as Bar Essentials. Also you can get Nitrogen Gas bulbs - so you can gas up your Stout just like the bars do. Go to here: https://www.creamsupplies.co.uk/index.php?searchStr=FLASKS&act=viewCat The postage is relatively cheap too.