Every time I clean my studio my husband makes this comment "wow, you sure do have a lot of stuff." This is so very true! I've collected a lot of art supplies over the years. Supplies I purchased for both classes I attend or was teaching that end up collecting dust after the excitement has diminished. Other supplies were purchase because it was a good deal, or I was struck by an idea for a new project.
However, if you ask me what should I purchase to start practicing my lettering, I would suggest the following:
1) Good practice paper / sketch book to practice in whenever you want.
2) Pencils, different types
4) Grid pad for copperplate and graph paper
7) Tracing Paper - use to trace letters for books to practice
I know this sounds boring, but you will be amazing at what you can learn using a pencil and copy paper. Next, I recommend finding a guild and signing up for classes, to learn different lettering styles. I prefer to be in a classroom setting where I can see the tools used, interact with other students as well as with the teacher. But, if you decide to take an online class, take time and do your research, find a seasoned calligraphy teacher that is inspirational. Best of all you can purchase books and check out online videos to learn about tools and techniques.
Supplies in the above picture are, pencil, mechanical pencil, eraser, grid pad, ruler, Sumi Ink, McCaffery's Ink (haven't decided if I like this ink), two oblique pen holders with different nibs, little ink holders, and Schmincke Gold.