7:58 PM, Tuesday February 28th 2023
On lesson 2 it says this, "All the assigned work for this section should be done in ink, using fineliners/felt tip pens as described here. You may also use a brush pen if you have one, though only to fill in large areas of solid black." So the brush pen is totally optional, but it does speed things up.
If you're in the US, you can get a sharpie brush tip pen for $2-3 at Michaels (or probably elsewhere). I have one, and it works well enough for this stuff, but I'll take you at your word that you just can't at the moment, and that's okay.
As far as colors...I think it's more important to do the stuff now than wait for the exact perfect supplies. Just maybe say when you submit the homework that the colored fineliner is the only one you have access to, but you wanted to continue with the course anyway. I think most people will understand.