Bleaching hair tips?!

Okay so, I've been dyeing my hair for about four years now maybe. I've started with red, then did purple, then did blue. My favorite was purple. I've bleaches my hair about three times In my whole life. The first two times were done by my sister at home & the third time was done poorly by this girl who claimed be to a "licenses hair stylist" who was working at home. She endes up overbleaching my hair so when the color faded It was all pastel. But tbh It actually lookes nice. So after awhile of having faded color hair, I was tires of spending like 30$ on hair dye every couple weeks/months. So I bought brown hair dye & dyed my hair brown. It was nice at the time bc I've has colored hair for awhile. But after awhile I hated the brown, so I wantes to dye it back to purple but I've dyed my hair like brown I think like twice before, so I think the brown hair dye was more strong than the colored ones so when I tried to dye it back to purple, It didn't stick. I always thought It was bc of the dye brand I used, I usually used manic panic which Is the best, always made my hair vibrant. & I've also uses splat & the last time I dyed my hair I used splat. & my hair didn't come out at all how It was suppose to & I was so sad. Bc I really do miss having colored hair. I know I need to bleach my hair ro get the color, I also know It's really bad to bleach it myself, I should have someone do it, but that's too expensive. My hair is way more healthier now, this lady who use to cut my hair even told me, so I think If I were to bleach my hair again It'd be okay, but I know nothing about bleaching hair, my sister always did it but she doesn't live with me anymore, so Idk what I'd need to get. So can anyone help me out??