When it's time to replace Christmas light bulbs, there's no need to replace the entire string. You can simply replace those that are no longer lighting. Outside of the "mini lights" many people use on Christmas trees, most strung lights are C7 bulbs (just under an inch wide) and C9 bulbs (just over an inch wide) ... and Lighting Supply offers a wide variety, including clear, white, and colored bulbs (both solid and transparent).
See our Christmas light replacement bulbs here.
We also offer LED Christmas bulbs, which can save you a lot of money over time. (These are included on the page we've linked to above.) While LED bulbs are initially more expensive, they can last you a generation (or two) while incandescent Christmas bulbs could need replacing every 1-3 seasons. So the bulbs themselves cost more over time, not to mention all the time spent replacing them. Meanwhile, a string of 50 incandescent bulbs could cost you $20+ extra in electricity costs each season. (Based on 6 hours per night for 3 months.)
But whichever type you prefer, we have plenty in stock for you.