Take an old drawer and remove the handles. To make a lid, cut a piece of plywood or medium-density fiberboard to fit the length and width of the drawer. Next, cut a piece of foam to the same dimensions and wrap it the fabric of your choice. Staple or glue the covered foam to the plywood to make the "top" of your ottoman and attach the top with hinges, so you can open and close the top for storage. Add four legs screwed to the bottom of the drawer.
Find a discarded wooden spool, the type used to wrap electrical wire, from a hardware store. Cut a piece of foam to fit the top of the spool, and use spray adhesive to attach the foam to the spool. For a rustic look, keep the spool sides open and simply cover the foam with fabric, stapled on the undersides of the spool. For a more finished look, add wooden posts inside the outer edges of the spool to make a frame, and screw them in. Use bendable cardboard wrapped around the spool and cut to fit, then staple batting over the entire piece and cover the batting with fabric.
Make a simple box out of plywood or medium-density fiberboard, topped with foam cut to fit and attached to the box with upholstery glue. Wrap the foam and box in the fabric of your choice and attach it on the bottom of the box with staples. Add rubber feet or casters you can screw in.
Find two same-size sofa cushions or box-edge floor cushions, preferably ones covered in matte-finish fabric rather than slick, slippery fabric. Measure them and cut a piece of wood to that size. Paint the wood and allow it to dry. Attach four casters to the wood and simply stack the cushions on top of the wood.
For easy kitschy footstools perfect for kids' rooms, take several old phone books and bind them together with duct tape. Or, take four large coffee cans, hot-glue them together where they meet, then cover with foam and fabric. If you have a large popcorn container lying around, simply cover it in fabric. Or you can first glue foam to the top for a softer footstool, and then add the fabric.