I totally agree with mmlandrhallam, especially if you have dark hair to begin with. I stopped wasting my money on home dyes about 7 years ago and although my hair is regularly highlighted and dyed it is is very good condition.
My sister went to Box Hill TAFE (VIC) because her regular hairdresser (mobile) went on maternity leave and she was used to only paying $80 for cut and highlights. Her hair looked good too – she was very pleased, and I`m sure it was less than $60. You need to be careful going that light with such dark hair too, you might end up with fairy floss – which is what I ended up with after doing my own highlights and then using SUN IN for touch ups (don`t ask, I was a poor student at the time)…spent two weeks in QLD, sun fried my hair and I couldn`t get a brush through my long hair, it was cropped to my ears and dyed back to brown – hence the reason I gave up on home jobs….and I`m not even very dark naturally (light – mid Brown) Good luck though! 🙂