A ceiling fan! You can get a very inexpensive one, and they are easy to install.
Get a CD player or MP3 player for his room. You can play lullaby CDs and/or nature sounds, such as waterfall or waves. They also make sound machines.
Those are the best I can suggest. We never tried to keep everything quiet for our children, or block out noises and as a result they sleep very well. The two options above, though, are very affordable and will work.
Common sense and research
Personal experience and opinion
Mom of three!