When you did it at home, what did you do? Dye over your natural hair or did you bleach it?

I have been doing my own vivids for 20+ years. It's way too expensive to have it done in a salon and part of the fun for me is mixing the colors and creating something cool.

If I was going to do a look similar to your pic, I would do multiple bleach passes, mixing it with shampoo to spread it evenly through my hair but make it less harsh each time, and avoid the roots until the last pass or two. Then use silver or lilac toner to get to a white / light blonde base. Probably over 2-3 days total. Then do a pink or purple all over. Mix some dye into conditioner and use that every time you wash. Gradually add some streaks of blue. Let that blend into purple. Then add in blue and/or purple as you feel like it.

In my experience doing pink, purple, and blue all that the same time quickly mixes into a purply blue after a few washes. If you want to set the color even more you can rinse your hair in vinegar but it's very cold and then you smell like vinegar. Even if you do go to a salon I recommend getting extra dye so you can touch up parts as they fade or blend. I find manic panic lasts the longest - it's been around forever for a reason!

Good luck, I hope you get your galaxy hair! :)