That's an item you have to shop around for pricewise. How long and what type of usb transfer cable? There are a large variety seen at nextag and other shopping sites as well. You would have to be just a little more specific due to this. http://www.nextag.com/usb-transfer-cable/search-html
If thats all you are doing just transfer them over your network put both computers on the same domain and share a drive where the file is on the main computer and move them to the pc not that hard really thats how i do it and it was free that way and its not that slow either really...
For the most part the ones I run into are 6ft. long as a rule. If you have the shared domain option that will save time and any hassles if you generally have the laption in another location. You simply log onto that domain to share common files and folders. For stand alone purposes you would then need a usb cable for the direct transfers seen then.
You cannot use a regular ethernet cable it will not work you have to have a crossover cable if thats the way you are going to do it... Also dont buy the one from the dollartree they are total shit we used it at school to test it and out of 10 only 1 worked and it only worked for like 10 mins and then it died...