As a founder, it is your responsibility to carefully manage your startup’s resources, and invest your time and money in areas where you will see the highest return. This means that your decision to spend $1500 on a three-day conference should be based on expected returns, not just a decision made on a whim.
In order to do an effective post-mortem on the return on the conference, set aside some time before the event to determine your metrics for success, and use these as benchmarks to hold yourself accountable throughout the conference. For example, often times entrepreneurs attend events to meet new people, expand their network and get introduced to specific people. Make a clear list of the those you want to meet at the event and make sure you get the proper introduction. Other metrics for conference success could include recruiting, learning, discovering new innovations/ideas, or chatting about what you are working on.