Theatrical blood isn't cheap, costing many pounds/dollars for just a small 25ml bottle, so if your ambition is to produce a low budget zombie movie requiring gallons of the red stuff, you may find it quite expensive
Ordinary red stuffs don't cut the mustard - Red fruit juice is too thin and runny and ketchup isn't going to fool anyone. You need something viscous, deep red and slightly opaque - and cheap!
Luckily such a substance is not difficult to produce - In fact you may well already have in your larder all the ingredients you need to make very convincing fake blood.
So if you are looking for a way to make cheap, convincing (and edible) fake blood - Look no further, just check out the video below.