I suggest popping into [email protected] they'll know. They gave me belting DIY advice recently

One of my couches is currently on legs I made from a 2x4 and some lag screws, looks like shit but you usually can't ever see it so who cares

I am an expert. Or at least an upholsterer. When you say the leg broke, what broke? Did it snap? Did it push into the sofa? Some legs have a bolt sticking out and screw into a T nut that is on the inside of the sofa.

Sometimes that punches in and just spins when you turn it. You have to pull the bolt out as hard as you can and try to get those prongs to grab wood. Most legs are one of 2 sizes. You could find another leg and bolt it back on.

It may also be a block of wood that screws to the bottom of the sofa. The holes are probably hidden by the felt scuff pad thing.

There is absolutely nothing wrong with propping it up on a brick or book or whatever. If you want to be less ghetto, take a leg from the back and move it to the front so your guests can't tell your couch is propped up on blocks

I saw this in a TV show once

I think we're going to need some details or pictures of how your couch is constructed and how it broke to really answer this

Since you mention unscrewing the other legs, could you just go out to home Depot (or local equivalent big hardware store) and purchase 4 of something like this and replace them?

Legs can be made with Legos I know you have those.

You can use some old books as a temporary leg. They look cool too.

What do you already have on hand? What tools and materials?

If you had a cinderblock, log, car-jack, or other heavy / sturdy item, you could use that to rest the sofa on temporarily while you work on it. Since it's a sofa, you could even just tip the sofa on one of its sides (if there is room). Even a stack of books could work, assuming nobody sits on the sofa or uses it (which is a good idea while it's being repaired). Either way, you probably don't need to buy something to rest the sofa on.

In terms of re-attaching the leg to the sofa, it depends on what you are working with, whether there is a way to screw something into the leg. Imagining a wooden leg, I could imagine drilling a hole into the leg and into the sofa, then driving a wooden dowel into the leg and putting wood glue into the hole and around the dowel and then softly tapping the leg into the hole you made into the sofa - the dowel going in the hole, I mean. Sometimes screws can be driven in at angles, or you can make or use brackets that screw into both.

Not an expert but I've dealt with a few sofas over the years. I think your best bet is trying to replace either the broken leg or all of the legs. Removing the legs and resting it on something can work but you risk it sliding around. Sofa construction tends to be straightforward, the frames are mostly just a big rectangle made from wood, if its not wiggling around you are probably fine.

Not a specialist but, if it was me, I wouldn’t rest the frame on the floor or something else.

I presume that’s a front facing leg so : unscrew a wall facing leg, put it in front, go to home hardware (or else) and buy some wood that will fit

You're not getting a great answer without pics of the damage.

Remove the broken leg. Stack books to replace it.

A can a beans makes a good makeshift leg.

This thread is useless without pictures of the damage. We need to know the construction to have any idea what the best course of action is.

Search "couch riser" on Amazon for some ideas. These are intended for raising the height of a couch but could work as prosthetic legs. Might need to get creative on leveling to the right height though.