AutoCAD software lets you do two- and three-dimensional design and drafting on your computer. It supports a number of application programming interfaces, for more seamless automation and customization. At present, AutoCAD only runs on Microsoft desktop operating systems. At one point, it was available in versions for both Macintosh and Linux, but these are no longer available.
If you're in the market for AutoCAD software and you have a Windows desktop operating system, though, there are a number of places you can get it. Research the Internet for the best prices available; Google is one search engine that will pull up a number of different places you can buy AutoCAD software, and sites like Buy.com also pull up "best price" options for a number of products. In addition, there are light, scaled-down versions of AutoCAD that sometimes won't cost you anything to try. These don't have as much functionality as full versions, and usually only function in 2-D rather than 3-D drawings. You can, however, look at 3-D drawings created elsewhere in the light version. In general, you can expect to pay about $4000 for the full version, and $1200 for the light version. Buy autocad software
If you are a student or teacher, it's also possible for you to get a significant discount on AutoCAD software; for the student software, it has an "educational flag" included so that any drawings run off from it are marked as such; the software cannot be used commercially. Licenses for student and teacher versions are available either with 14-month limits, or they run perpetually. Visit the AutoCAD student community at http://students4.autodesk.com/?lbon=1 to learn more about getting a discounted student copy.
Buying used
As of May 2008, at least one court case has also affirmed the right for users to sell used copies of AutoCAD at similarly "used" rates. AutoCAD software company Autodesk had fought the right of this particular seller to in essence "resell" used copies, but a Washington state federal district judge upheld the seller's right to do so. Autodesk had argued that it doesn't actually sell the software, but licenses to the software. Nonetheless, the judge in the case struck down this argument and upheld the seller's right to do so using the First Sale Doctrine, which guarantees the right to resell used copies of copyrighted works. Therefore, finding used copies on eBay or some other similar site may be one way to find inexpensive software that's still inherently usable, although you may have to pay a licensing fee.
Finally, your school may also have avenues to purchase used versions of AutoCAD software, if you need it for your studies.
Need to learn how to use your software?
The Internet abounds with CAD tutorials, many of them free, and there are also many forms specifically devoted to AutoCAD software for those who have difficulty using it and need to learn more about it.