I have strawberry blonde hair, and my eyebrows and lashes (although very long) are so blonde that you cannot see them. Being a young lady in this day in age, I just want to look like everyone else. The trick is to learn what works and what doesn't.
About dyeing your eye brows: it can be expensive if you do it excessively. The color usually washes out within two or three weeks, depending on how dark you go. It's nice if you're going on vacation or something, but I personally recommend using a pencil (check out Maybelline's brow pencil) to shade your brows in; use light strokes going in the same direction, and don't over do it (caked on brows look fake and unnatural).
I'm not going to lie. Dyeing your eyelashes kind of burns, and is generally more expensive than dyeing your brows. Pain is a good indication that it's not good for you; stick with mascara.
If you're a light blonde, I would try a soft black or dark brown before you apply the blackest black shade of mascara. The trick is for the coloring to look natural, so play around with mascara and brow colors before committing to one. I prefer applying mascara on my bottom lashes as well, but some people prefer using a light eye liner instead.