Sales tax is a tax that US government charge for certain goods and services. Every US state have it's own sales tax, some higher, some no tax. ShipW is based in Delaware state, so there's no sales tax for online purchases to your US address. You'll have to pay the shipping though.

I don't consider me as a graphic designer, but I use photoshop very often when it's came to make a few small changes or make a logo image, or anything else. I have to admit, at the beginning I used other tool to make some changes in photos, because Photoshop was like a airplane for me. Too much functions that I cannot understand, but after a few youtube tutorials and searches when I had to do something specific I started learning the basic functions, and now it's the primary tool when it comes to images.