Fidget can be downloaded for completely free. You can also run Fidget directly from the website.
Fidget comes in two different flavours, Scratch and Desktop edition.
Note: .sb3 files must be run within Turbowarp.

Fidget (Normal Edition)

The current edition of Fidget that receives regular updates. Recommended for computers.

Alternatively, you can run an older version of Fidget here.

Scratch Baby (Legacy Edition)

Scratch Baby is a legacy edition of Fidget that no longer receives updates anymore. Recommended for tablets.