Start with a good quality harmonica with a plastic comb.Do not use a wooden comb harp like a Marine Band until you become proficient at getting single notes.A wooden comb is not as responsive as a plastic comb unless you are able to direct all the air into one hole without any air spilling over to the side holes. It will take practice in order to do this. The trouble with $5 harmonicas is that you might get a good one and you might not.Many in that price range are out of tune. It is best to spend a few more dollars and get a good plastic comb harp like a Suzuki Bluesmaster which can gotten for around $20 on the internet.The cheapest good quality harp is the Huang Silvertone Deluxe which can be gotten on-line for around $10. Start out by playing simple folk melodies until you can play each single note clearly. Learn to play those simple songs in both the puckering and the tongue-blocking methods. Tongue-blocking will allow you to add chords to your lead notes,octaves,percussive single notes and various other special effects. When you can do all that well then you can start trying to bend notes which is essential for playing the blues but thats another program. If I had to sum-up my advice for a beginner in three words, it would be practice, practice, practice.