For a free and immediately useful sound level meter please consider downloading one to your smartphone from the National Institute of Occupational Safety and Health.
Simply go to your phone's App Store and search for: sound level meter. There might be a number of options, but the NIOSH app is simple and can be trusted.
Is this as good as a calibrated studio level device? No. But it's good enough to get a useable level reading to set a baseline or observation.