If you are a full or part time employee at a care facility PickaShift can quickly alert you to shifts that have come up at short notice. You can then choose to either claim that shift at the advertised rate or wait and see if the hourly rate goes up. As the time ticks closer to the start of the shift, it is likely that the rate will increase. Be wary though, if you wait too long someone else may claim the shift before you.
The app also keeps a record of extra shifts you have done and how much you have earned.