The Inchworm can grow a full size in half-size increments, giving you an unprecedented three shoe sizes in one shoe. It’s aimed primarily at toddlers and runs in children’s shoe sizes from 10 to 5. When your kid outgrows their current size, press a button on the side of the shoe and pull on each end to extend it another half size.
The shoes are available in a variety of styles and colors and cost just between $20 and $50, which seems like a pretty good deal to me. Better, anyway, than shelling out for three pairs of shoes in a year or so.