Are the rails she took from her minivan square or round? Were they top-brand, or something else? If they were top-brand, then the square ones are Thule and the round ones are Yakima. Both of their websites have configuration wizards in which you can punch in make, model, year of her car, and whether it's got factory racks and such, and will walk you through the options available.
The advantage, as I understand, in Yakima and Thule, is that if you follow their instructions, you've got a pretty good likelihood that the racks won't whistle in the wind. If you go with one of the other brands, it's much more up to you to deal with whistle.
You can often find Yakima and Thule components on eBay and CraigsList. I bought my Thule rails and towers from a guy I found on craigsList, then bought the fit-kit for my car. Retail value would have been between $300 and $400, I paid $95 plus $50 for the new fit-kit.
The advantage, as I understand, in Yakima and Thule, is that if you follow their instructions, you've got a pretty good likelihood that the racks won't whistle in the wind. If you go with one of the other brands, it's much more up to you to deal with whistle.
You can often find Yakima and Thule components on eBay and CraigsList. I bought my Thule rails and towers from a guy I found on craigsList, then bought the fit-kit for my car. Retail value would have been between $300 and $400, I paid $95 plus $50 for the new fit-kit.