I got one for my girl this past Valentine's Day. Got it from eBay from the person listed as Proudparents or something, they sell a ton of them. You can also get the cartridges from them for cheap. You're probably not going to find a better deal online or B&M. Don't buy your wife something refurbished, used, or otherwise unless she has specifically stated she's ok with that. I figure most ladies like their stuff new unless it's something like a car. Spend the extra $70-80 for a new one. It's still cheaper than if you got it from Amazon.
If/when you get it make sure you update the software/firmware, it wasn't working for custom stuff the first month or two we got it because their firmware was out of date. She could use the cartridges, but couldn't do the really creative stuff that requires the PC. Otherwise it worked fine without it. You'll probably want the little spatula to lift things off the mat as well. There are a few little things you want that aren't included. Hope that helps some.
