What is the difference between the salon hair colour and the shoppers?

I want to colour my hair. I dont want to go to salon. Is there a huge difference about salon and shoppers hair colour plz helpWhat is the difference between the salon hair colour and the shoppers?
The salon dyes are more gentle towards your hair, and the fact that you have someone who knows what they're doing helps.What is the difference between the salon hair colour and the shoppers?
One of the main differences are the prices ye a shop bought on is cheaper than a salon , but at least in a salon you will no what your getting allot of box colours say something on the front that its this colour but once you have done it , it turns out wrong ,if this happens in a salon it can be fixed straight away and no harm has come to you hair but with a box colour thay damage and damage every time you use one ,also a box colour is more or likely the one that you can have a reaction to.
I am a licensed cosmetologist who specializes in colouring hair. In my opinion, the biggest difference is that a trained professional knows the Theory of Colour. For instance, if you have dark hair and want to change to light hair, you must know your natural level of colour, levels of lift, underlying pigments, hair texture and condition. These are just a few things that need to be considered before going from dark to light. If going from light to dark, you need to know what your natural level of colour is and how much darker you want to go and what tone you would like to deposit into your dark hair. Sometimes people get lucky and what they buy and apply themselves works out fine. However, if you aren't lucky, depending upon what you do to your hair, you could end up looking like a calico cat and you would then end up spending much more money for a professional colour correction than you would have spent had you gone to a professional in the first place. I make a whole lot of money correcting colour so it's up to you to decide. Hope this helps.
price to start... the solutions are better for each hair type. color from the store feels so general.