Depends where you're from. In Ontario, going in and pleading guilty will always save you money. Showing up early and settling with the crown attorney before you go to court will also always save you money. If you're not looking to avoid the fine completely, your best option is to go in, plead guilty, and then appeal the decision no matter what. Hopefully, they'll forget about it. Otherwise, pay. If you have a full-time job, it's usually not worth it to do this, and they know it.