I have had my Sansa Clip for about a year. Yesterday, sound stopped coming into the left ear bud. I have switched to another pair of ear buds and also tried reversing the right and left earbuds but still have the same problem. Is only solution to buy a new Sansa?
That, or take it apart and check connections etc.
Are you still within the original warranty period (1 year or 2 years)?
You also can try pushing a plug in and out repeatedly into the headphone plug, trying to clean possible obstruction out.