Summarize this article in one sentence.
Lenses come with a number of added features, such as scratch-resistant coatings and color-changing features meant to offer ultraviolet protection. While many of these features do effectively provide what they offer, they are also largely unnecessary. If you have a tight budget, skip the extras and stick with a basic prescription lens.  If you purchase your eyeglasses from a department store or popular eyeglasses chain store, you may be able to find coupons in magazines or online. Many carriers cover a portion of the cost for eyeglasses if you buy them at specific places. Depending on your coverage, you could have more or less choice available to you.

Summary:
Only buy what you need. Shy away from brand names if your budget is low and you don't need to get the latest styles. Look for coupons. Check with your medical insurance.