The closer to Bayfront Park, the more expensive your hotel rooms will be. However, nothing quite beats the convenience of getting out of ultra and walking to your hotel. Alternatively, you can get a hotel near one of the stops on the Metro Mover.
Getting a hotel near the airport will be much cheaper, but be prepared for a lengthy drive or more expensive uber ride back home.
Hotels and Airbnbs in South Beach can be quite expensive as well. You'll usually have to take an Uber back to South Beach, which can be expensive with surge pricing. On the plus side, there are some after parties in South Beach.