I have a rolling one I paid about £25 for. All I do is roll it slowly so that it catches all the unused litter under a grid & the muck can't pass through the grid so you roll it more, it flips on the lid & falls into a tray to pull out & shove in a bag. Don't have to touch a thing & very easy to use but is quite large.

Doesn't work with wood pellets, though.