First thing you need is software while there maybe other software thats free in my opinion in the long run your going to need Adobe photoshop currently priced at $999 or $349 for an upgrade. Next thing youll need is a wacom drawing tablet, the smallest wacom intuos 4 by 6 is $229.00. You will also need a reasonably good high quality monitor, I state this because while some will say well I have a monitor already it may not be suitable. The reason is color monitors are fairly cheap these days but the cheaper ones tend to give you poor color values. Next you will need some training, there are many ways to obtain training, theres a ton of tutorials on the net or you will need to pay for training. Again these are my opinions but I think your best bet is go to your community college and sign up for a class and supplement with tutorials you find. Cost for a class will vary here your talking about a $100 plus materials and parking.
Ok these to me are the basics for a beginning designer who has looked at it a bit and decided they really want to do this. Now lets take a look at what goes on beyond the basics. I'm basing this on myself and some designers I know who are pursuing design somewhat seriously. While community college classes and tutorials are a great start to go beyond that your going to have to get advanced training, that comes at a cost. Typically classes run anywere from$800 to several thousand dollars depending on the intensivity of the course or workshop you are taking. Add to that books and magazines you will need for reference. Next you will need a high quality digital camera, a good camera of the quality you need is going to run you about $700, you also need a tripod and lighting, you can get a reasonable tripod for $80 lighting is quite expensive a beginning lighting kit will run $300 to get the bare minimum.
Some of these things you will not need in the beginning of your designing career but as you improve you will need to add them. Ok you say did all that done right? Well that depends on your desire to improve and the quality you desire to reach. For me and professional artists I speak to training and learning is a process that never stops unless you wish to become stagnant and not grow. In addition to taking classes in photoshop I recommend taking classes in drawing, painting and color in design using real medium not the computer. Why you might ask? this gives you a basic fundamental ground to work from so you will understand why things work.
This doesnt even touch the costs and training 3d modeling which is starting to become one of the tools that designers are needing.
One last thing before I get off my soap box, the phrase "its free all it is is your time" well many of you have or have had a job in real life where you collect a hourly or weekly paycheck. I highly doubt if you went to work tomorrow and your boss said oh we have decided were not going to pay you today after all its just your time yould be very happy.
I recently saw a tv show the name escapes me but it was based on the cost of your time on normal mundane activities such as doing laundry, dog walking, taking your pet to the vet to loading your ipod they calculated the time these things took and how much time you were losing to them each week and it amazed me when you started totaling it all up how much time we lose just running errands. The focus of the show was the many services out there that you can hire to perform these tasks, who knew you could hire someone to load your ipod and set up play lists? My point is your time has value and it doesnt really come free as its at a cost of something else, it takes time to take classes, it takes time to seach the net for tutorials, it takes time to make dinner and do laundry.
So perhaps before someone says its just your time it costs you nothing maybe think twice....