If you are not sure how long you need it for your research, it'd be good to try a similar tool which is free or cheaper, or use the demo or trial versions (most of them are actually full-function versions with limited days or times). If you are lucky, you can even get a free education copy from the developers. Here is a list:
ATLAS.ti 5
http://www.atlasti.com/download.html
Ethnograph 5
http://www.qualisresearch.com/
QSR Nud*ist 6
http://www.qsr.com.au/products/productoverview/product_overview.htm
QSR NVivo 7
http://www.qsr.com.au/products/productoverview/product_overview.htm
MaxQDA 2
http://www.maxqda.com/maxqda-eng/index.htm
HyperResearch 2.6
http://www.researchware.com/hr/