Design professionals, graphic designers, photographers...
Graphic designers and artists
You would use the marker/pen/brush tool, or the paint bucket tool.
you can use any photoshop but i tend to use CS3 or CS4
Use it to see if they like it enough to purchase it or not.
One would need Photoshop Lightroom to organize and store their photos. There are many other options and software which one could use. Photoshop Lightroom is a very popular software package highly rated by many consumers.
There are several programs you could use, such as AutoCAD (architecture version) photoshop, etc. AutoCAD would be for building the general design and finding the dimensions. Photoshop could be used to see how a deck would look on your yard.
Most digital and graphics design artists use photoshop. Those who can't afford Photoshop usually use GIMP or Corel Paint Shop
When you show your products photos to your customers and need to edit them, you will use adobe photoshop.
Photoshop Elements is Photoshop but with less features, so Photoshop is better but it is professional level software. For home use or to get started Photoshop Elements is OK.
No, they are separate programs or software's to use and to buy.
It would depend on what one wishes to use the font for, some good sites that list and offer fonts for Photoshop are tekplz, myketech and the techgame.
Adobe Photoshop tutorials online has thousands of free tutorials to teach you how to use their photoshop. You can also use photoshop or adobe to find all the answers to your questions as well.