i was thinking of buying a cheap bag £13 and putting a wide tube up it but thought it on a L shape base that i stand on to stop it falling.....???
Don't get a cheap bag - they're a false economy.
Where are you going to mount it - ceiling hooks can be a particularly bad choice for a heavy bag.
You can get freestanding stands, that you put weights on to steady them - can't say as I've ever used one - there's also those slam-man type efforts, with a filled base and a shaped body type thing - you can get generic ones that look just like a normal bag.
Truth be told, in a house situation, an externally mounted bracket, either on an external wall, or in a garage, if you've got space and the walls are solid.
If you live in a flat, I suspect the slam-man type things are probably the best choice, because mounting one on a wall, or using one with a metal frame, is probably going to create so much noise for other neighbours, you'll get them using you as their heavy bag.
If you can mount one on a solid wall, either in such a way as it won't make your neighbours hate you, or in a garage, you'll be fine - otherwise, consider going to a boxing gym, or similar type of gym where you can use one.
You want a heavy bag to be a decent size, weight and length - not overly heavy if you're new, but not too light either. Cheap ones are often a false economy - either too light or fall apart after a bit. People do make their own - but decent materials for the bag, and decent efforts at filling.
Get decent hand protection, bag gloves / mitts, or if you're experienced, reasonable weight boxing gloves. Make sure your technique is good - it's easy to damage hands and wrists.
Have you boxed before?
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