So, I finally found an affordable heavy bag to play with at home. It comes without filling, though. I notice some people use sand, others rags, etc. How do you fill yours? I'm hoping for a cheap and easy way.
The bottom with sand or rice, the sides with ripped up cloth or cotton wool, the middle with anything from the insides of an old mattress or really compressed plastic shopping bags or even cut up bits of rubber (mixed with a bit more old cloth to fill in the gaps).
Go to a joinery place and fill with sawdust. Sawdust is good because you can make it more compact as you continue and also you're helping a local business get rid of waste
There's some great suggestions here actually. I tend to stuff the outer lining of the pad with whatever good quality foam I can find. Then fill the entire bag with sand (cheap, cheerful and turns solid quickly).