Following are two different types of punching bags. To mount them onto a base, you could use a similar method as mentioned before, with a PVC pipe and an old parasol stand, or maybe you even have a small (but bigger than a gallon) water tank and could fill that one up with sand.
Probably simplest punching bag
- Get a rice bag.
- Fill it with rice if it isn't already.
Do not punch without gloves. You could still wrap it with duct tape to make it even more durable.
Using old clothes or grocery bags
- Get a laundry bag or (at least) two garbage bags.
- Fill it with (shredded) old clothes (hoodies, jeans, etc.) or stuff it with a lot of crumpled up plastic grocery bags.
- If you use garbage bags I recommend covering the bag with one or two layers of duct tape. To be sure, you can also wrap the laundry bag with duct tape.
To protect your wrists, also use gloves when punching this bag.
Be creative! Use this as inspiration. You can basically use any type of bag or stuffing. It's just a matter of how hard you like your punching bag, or in this case, punching dummy.