Data Crawler for Product Info Customization

I am looking to have a website spider/data crawler made or tailored so that will allow me to gather product information from other sites to put into my database. I've been playing around with a product called Web Content Extractor, which has a free trial. Before I buy it, or something else, I want to make sure I can set it up to do what I want, and have some basic steps for how to change it. If you think you can help me out, I am looking to gather data from women's clothing retailers in the following parameters: category (dresses, shirts, etc.) title description details price color sizes measurements features photos Sites I would like to do a test crawl on are: asos forever21 delia's