So I accepted a shop this morning and about an hour later they added a bonus to the shop. Mine doesn't show the bonus. Should I cancel and pick up one with the bonus? Does cancelling a job have a negative effect? I've only done about 5 shops so I've never had this happen so far.

I just took the $3 loss but I'm still curious about an answer to this.

You can ask your scheduler if they would match the bonus but I would definitely not cancel. You nearly always get a bad reputation for cancellations even if the system lets you reassign the same shop.

I agree. You will probably get a bonus sooner or later.