DIY hair colour

I’m looking for advice for brands (I live in Canada for reference) to use or tips for colouring my hair at home by myself. I just simply cannot afford to maintain it at the salon right now in this economy *sigh*. Looking for recommendations that aren’t as harmful for my hair, open to semi-permanent too I think? I don’t know. My hair is dyed dark chocolatey brown, and my natural root comes in as a lighter mousey (as i call it lol) brown, just wanting to keep my dark brown colour and maintain my roots as they grow out. No gray hairs yet. Help a sister out! Thanks in advance <3