In the USA?

If you have not yet learned the "joy" of thrift store shopping, do. With the thin digital tvs replacing all those deep analog tvs, there are a lot of tall, wide,deep tv cabinets being donated to thrift stores. Some of them are of the upscale, real wood variety with a lot of hidden storage all around the tv area and even doors over the tv area. All you need to do to make some of them usable for linen or toy storage is remove any existing back with all its holes and add a solid piece of thin plywood (or paneling) to seal the back (Your local big box store will cut to size for you for that.) and add any shelves you want in the large tv space. I've even see a few converted to a toy kitchen, others to pet homes. Before investing huge sums of money in new storage for a play room, at least take the time to make a few trips to any nearby Habitat for Humanity Restore Store and/or charity thrift store of any kind. Inventory changes with each donation and sale. After the holidays changes reflecting a need to make room for new purchases and spring remodeling season usually have the most options.

We had drawers built into a low bench that was a windoe seat the drawers came out on casters and could be wheeled around the room for easy pick up and put back no one ever knew there were toys in there when we entertained. worked great fo legos with smaller wood boxes inside My Dad actually built it

Fabric covered storage boxes would work. Google "fabric file boxes". When the last kid outgrows the Legos, you'll still have useful boxes.

Large wicker or rope baskets would look great and are easy to move. These are from Target.

Also, a wicker or rattan laundry basket with lid could look good depending on your decor.

Our kids liked the legos to more organized so I guess it depends on what your kids like

Thank you for all the great ideas. We tried a few different ideas and then decided to repurpose an existing space. The built in lower cabinets on either side of the family room fireplace were emptied and we put in shallow Elfa mesh drawers (easier to sift through to find a favorite piece) with dividers that we could customize. The intent is to get a new coffee table that will work for building but that can be cleared when they are done or we want an adult space back. We kept a couple of odd shaped shallow shelves in the adjacent room for storing favorite builds. The sort was completed yesterday and everyone is excited about the potential functionality, but the true test (putting the Legos away) is yet to come.