There's plenty of free sites out there. I would start with the free sites to get an idea of what she really wants to watch and go from there. I'm a woman and love some of the following sites.

pornhub.com (has a great list of videos by category)
wunbuck.com
homemadefuckvideos.com
tehvids.com
crosscuntry.com
burningcamel.com

These are a few of my favorites that I visit at least three to four times a week. There all totally free, so that might help give you and her an idea of what she really wants to watch.