While cheap all you can eat buffets like Golden Corral are typically an American thing, buffets tend to be more of an expensive international hotel thing while in my end of China. That being said, there are all you can eat spots in China that are extremely affordable -- conveyer belt 小火锅 small hot pot.
Basically, you are sitting at a metal conveyer belt as ingredients scoot by you in bowls. Some of that could include slabs or cubes of duck blood.
Congealed blood may sound utter disgusting, but it essentially has the floppy consistency of tofu with hints of copper. I am not a fan, but I don't outright hate it. Given a choice in a cheap place to eat like this, I can opt to ignore, which I always do.
If I had to compare these sorts of places back to America, they would be like New Jersey diners. The food is extremely cheap, and you leave satisfied. This particular place is around the corner from where my girlfriend and I live. It's part of the neighborhood -- even to the point where it came highly recommended by our Chinese neighbors. We live in a housing development where her and I are two of three expats in the entire community. There are foreign hubs Changzhou. I just don't currently live in one of them. However, there in this one particular small hot pot place, there is one thing I absolute love.
Small hot pot places with conveyer belts are easy to find. The place around the corner from me has a small iron grill plate next to the bubbling hot pot. So, instead of being married to eating soup for dinner, you can grab and grill up some fresh mackerel.
Or just other random things.
The culture of "all you can eat" differs depending on the culture you live in. In America, you can heap up plates of food of what has been prepared for you. In my end of you China, all you can eat actually requires you to cook for yourself. I like that.