If you don't have space for plastic dustbins / crates, and you don't have a bath to fill, you might try this.
Get a sheet of semi-rigid material that can be rolled into a tube (eg large opened-up and split cardboard box, bamboo tatami mat, foam camping/yoga/picnic mat, etc). That plastic stuff with two flat sheets with a corrugated layer in between, (
airex?)(Coroplast?) that they use for signage, would probably be ideal if there's any lying (or blowing) around.
Form it into a tube, with some overlap swiss-roll stylee
Put a large bin bag inside the tube, and fold it over the top. You need a good overlap, preferably double. Obviously the dimensions of the tube and bag should be roughly compatible height -wise. If your bag is too short you might have to tie something around the bottom of the tube,and/or use two bags, one inside the tube, one outside.
Half or 3/4 fill the bag with water. The weight of the water expands the tube until its stopped by the bag overlap coming under tension. The whole thing is pretty stable, and the overlap protects the cardboard (if thats what you had to use) from spillage or rain if you use it outside. If you need a lid (don't see why you would, really), slide another bag over it.
I used this to store and collect rainwater in the Tainan post-Morakot outage. (It had to be rainwater because I hadn't prepared, duh!, and there wasn't anything else.)
I've also used it as a portable wash-tub when camping/travelling.
An advantage of the flexible stabilised bag is that it can be assembled around a roof gutter downpipe. It is often impossible to get a rigid bucket under one of these without cutting the downpipe.
Also, buckets are at a premium in such troubled times, and I'm sorry to say, someone knicked mine when left under a downpipe.
We reach for the sky. Neither does civilisation.
(Incidentally, if the search button is your friend, you must have some bloody useless, dysfunctional friends)