Big entry fee hike
Officials of Rancho Santa Margarita CA raised entry fees from $20 to $30 for the Rancho 5k, to help close a municipal budget gap.
That's a risky strategy, since runners don't really care about the financial health of the town and are likely to judge the fairness of the fee based on what they receive at the event.
Rather than adopt a huge fee hike in one year, it's a better idea to consider smaller increases each year. That way, you'll keep pace with rising expenses and not risk losing participants with a suddenly higher-priced event.
Racing is not a necessity (at least for most people, including runners) and raising entry fees may not be a good strategy. Most local governments opt to levy additional fees on event producers (not participants), businesses, and other license applicants who have little choice and will fork over the additional fee.
Runners can easily opt to race elsewhere or not race at all.