There is an undeniable advantage with people who look better than the average person. No matter how many people would repeat the mantra that inner beauty is all that matters, they can't delude themselves to the reality that society favors those who look presentable and are aesthetically pleasing. This is in part because of people subconsciously recognizing the fact that good looking people put in the effort of making themselves stand out. It exudes an aura of self-worth and confidence. This is why slobs in job interviews are highly unlikely to get a positive nod from the interviewer. Or even from their fellow applicants for that matter.
This practically means that putting in the effort to look great is an investment. It's not skin-deep, as most people would decry. It's a reflection of how highly one thinks of themselves; people may not know it but they are attracted to the charisma from confidence. Do note however that looking good doesn't always mean spending an arm and a leg. There are beauty salons like http://mylocksandlashes.com/ that are able to provide amazing services at a reasonable price. Their satisfied customers as well as the resulting look of their customers should be testament enough for their reliability.