Need help with my hair going blonde

Hey

I really need help with my hair!
Two weeks ago I had my hair healthy dark brown and I decided to go grey.
I bleached my hair 3 times to get it to the lightest colour possible colour and dyed it grey. However the whole bleaching process took a lot of money because my hair is so thick so when I ran out of grey I compromised and dyed my roots semi permanent blue. It looked great the first few days however when I washed it all of my hair went mouldy green colour which I'm hating.
Tomorrow I want to dye my hair kind of medium ash blonde.
I don't want to bleach my hair again as it will destroy it, I just need help figuring out if a drugstore box dye will work fine? I'm scared it will go a weird colour.
Both grey and blue I put in my hair are semi permanent but I don't have the time and money to strip it.