Rolling Work Cart
I spend a lot of time under the layout, but that work is made much more comfortable with an old roll-around desk chair (set as low as it will go), and it's made much more convenient with this little contraption I cobbled together:
I got a 3 drawer cart, clamped a piece of plywood to the top to form a stiff tabletop (I've got lots of plywood lying around now that I'm using foam for my subroadbed!), and put another, smaller 3 drawer organizer on top of that. The smaller drawers hold small tools, my electrical stuff, and tracklaying stuff. The larger drawers just hold extension cords and larger tools (drill, saber saw, soldering iron) for now, but there's plenty of space for more there.
So there you have it - a convenient, rollaround work cart for under $30.