No Adobe products are free except for Acrobat Reader. Adobe Photoshop, full retail version, will run you $600 to $1000 depending on whether you get the Standard or Extended version. There is Photoshop Elements, which really is the best thing for people just starting out with Photoshop. Version 7 is available for PC and version 6 for Mac; Elements runs about $90. Most people will find Elements more than adequate; many people who think they need full Photoshop will never use more than 10% of its capabilities.
If you still need full Photoshop, and you are a student, you can get the academic version for about 1/3 the cost of the retail version. Check with your school to see if they can assist you with the purchase (you do have to prove you are a student to buy and use the academic version; Adobe has tightened up the rules because a lot of people who were not students were acquiring the software.)
Note that it is illegal to try to get Photoshop for free, that is software piracy, which is stealing. People forget there's a reason these things are not free: Adobe is a commercial company. They make money on these products, but it's not just the company. There are hundreds of employees at Adobe who work their butts off getting these programs developed and functioning. The money made pays them for their work, and helps pay for further development of new programs and continuing advances to existing programs. So when you ask to get something like this for free, you are not just stealing from the big corporation, you are stealing from the people who do all the work. And since companies have to spend money to prevent piracy, they pass on some of the cost of that to their customers. So those of us who buy Photoshop and other programs are also paying to try to stop piracy.
If you can't afford any of these versions, you may want to look into some free alternatives. The most powerful program and closest to full Photoshop in its capabilities is the Gimp. It is free, Open Source software, you can find it at www.gimp.org. It can be hard to learn, but there's a large community of users that can help you.
Another alternative is Paint.net. It is not nearly as fully featured, but is very popular. You can find it at www.getpaint.net.
There's also the on-line image editor called Sumopaint. It works in your browser using Flash, has several features that both Photoshop and Gimp have, and is free. Find it at www.sumopaint.com.
I hope one of these works for you.