If it’s an interior door, just carefully detach the molding around the wall adjacent to the door with a sharp knife. (The molding is attached to the wall using very small nails, so detaching the molding shouldn’t take too much force). That will give you access to the latch. Then use a screwdriver to push out the latch out of the wall to open the door. Once opened, you can disassemble the doorknob from the inside.

Attach the molding back, using either a small rubber hammer or even just your hand so that you don’t damage the paint. Repainting can be a PITA, as even if you perfectly match the color it could still stand out.

Did this multiple times when I lived in an apartment and locked myself out of the room. If don’t correctly, it should cost you nothing and can be done fairly quickly.

Exterior doors are a different story. That would be the only time, I’d be spending money on a locksmith or hacking the door handle apart. Doing that on an interior door is just unnecessarily risking damage to the door and surrounding walls.