Right now I have a healthy mix of 'cheap' sunglasses and name brand glasses... I like each pair for their own reason. So I definitely think a little splurge on sunglasses here and there is a great investment (especially since they come with such nice cases in order to avoid the classic "I just sat on my glasses and broke them!" incident...)
Selima Optique of NYC just partnered with J.Crew on a REALLY fun line of sunnies... I seriously want a pair of each style. They are so fun! And the splurge and/or save might surprise you here... the Selima Sun for J.Crew are almost a quarter of the price of the Selima Optique styles... SCORE!