I have to agree with retrodon. If you want something permanent that you'll use year after year, go with the resin. You can also find it at hobby stores that sell trains and their landscaping as it's used to make water. But as most have mentioned, the stuff isn't cheap.
So, let's say you're going to want to try it just for a year and then decide if it's going to be a permanent part of your haunting. Definitely go the homemade theatrical blood route. Here's a few examples of how to make it from household products. It's very inexpensive and just as realistic as the store bought more expensive varieties out there.
https://www.wikihow.com/Make-Fake-Blood . It will easily last you all night staying nice and shiny looking. You might even wind up with a creepy insect or two that finds all that sugar irresistible. Here's a link to a video that can even help it wash out of your stuff if you think you might need that option.
https://youtu.be/hI7ttHwv10k?t=260
Remember that whatever you do, blood isn't just red food coloring. That's why all but one recipe on the links here use some form of brown or green to make the blood darker. Our blood starts to oxidize the minute it hits the air, and as the cells die, they grow progressively more brown. That's why a murder scene never has that garishly bright red blood you see in most police shows on TV. If you're going to go bloody, you better bloody well make it look real.
