Interesting video. Can't say it was a lot of help as such to me, because I don't paint pictures. I paint my wooden figure banks (may go back to making them), but since I lay out the pattern with a fine tip magic marker, it's like painting by numbers, without the numbers. I do paint the occasional cane handle, very occasionally, but normally only for my own personal canes, because I find painting them a real PITA. So any I paint for someone else will definitely boost the price up. I did learn a bit from the video - I looked at my brushes, and actually have some that are pretty darn decent. Even got two small foam brushes that I have not a clue what I'll use them for, but won't toss them. Got the foam brushes when I picked up a pack of I think it was 24 brushes, from WallyWorld, for around $2. Some of the brushes are quite decent, some I think are brushes for kids doing water paints, with the majority somewhere in the middle. I consider them well worth the price, because for the type of painting I do, they work out just fine.
Now, all my painting is with acrylic latex. Relatively inexpensive, water cleanup, no bad smell. I get the small cans. Very easy to mix custom colors, and thin it down enough and it works about like a dye, except you can make it any color you want.
I keep my brushes in a pencil case. Works well, but with my last brushes buy, it is pretty much packed. So found pencil cases with a hinged top that will work perfectly, should hold all my present brushes nicely, and will get some extras, so if I run across another good deal on brushes I will be have somewhere to store them. Also use those cases for my mechanical pencils, my pens, and my colored pens. For my colored markers have a deeper case that hold them all nicely.