Maybe you could try using free digital painting softwares, there are a bunch out there, like: Krita, Gimp, Medibang, Fire Alpaca, that way you can get the hang of how they work in the meantime.
I don't have a tablet or any digital drawing thangs. So if I want to color something digitally I use my mouse. Honestly I never had a problem coloring with it. Of course there are limits to what you can achieve with a mouse and I suppose it's time consuming, but it can get the job done.
If you're able to buy a tablet, give it a shot. But if you cant have one, don't let that stop ya from making comics.
Cheers