I've used all kinds of things over the years but tend to stick to food items because they're cheap and disposable.
A hollowed out cucumber is good. Get a thick one so you leave plenty of wall thickness. You can either make just a small hole in the rounded end (to let the air out) or cut the end off so that the whole head of your cock pokes out.
A melon is good too but make sure you get all the sharp seeds out!
A jar filled with part cooked pasta, the spiral stuff is good (fusilli?) Don't fully cook or there's no sensation, cook just enough to soften the hard edges. Or fill the jar with coarsely ground beef.
Roll a big slice of thin steak into a cylinder and put some elastic band around it. This is a bit messy and more expensive but very realistic
There's loads of stuff you can use if you take a different look at the shelves of your local supermarket. PM me if you want to talk more.
They said I'd go blind but I'm managing just fine with the spectacles.
Happy to receive PM's from like-minded onanistas.