I don't like John Frieda's shampoo and conditioner very much since I find that the shampoo feels like plastic, and the conditioner is full of slippery silicones. That being said, I've heard amazing things about some of their other products, such as the iconic Frizz-Ease line.
This lightening spray is pretty much a heat protectant, mixed with a touch of bleach and some citrus and chamomile extracts. The product is not suitable for medium brown, or dark coloured hair since it would turn rather orange. You can see the full product details on the John Frieda site here.
For touch-ups, I'll apply a few spritzes to the top half of my head to lighten up the roots. When first building up the base colour, I'd recommend using about 10 sprays max. throughout your hair. For touchups, use about 5-6 sprays (depending on your hair colour and desired highlights).
The results are exactly what I was looking for - noticeable highlights, without looking fake or overdone. For a drugstore product thats around $10, I couldn't be more pleased.
See the step-by-step DIY and a full review in the video linked here: https://youtu.be/nr01ajpJfNA