Hello.
Here's the thing. Everyone has a different definition of a lot of money, so I don't want you to spend more than you can afford, obviously. However, I'm on my 3rd machine and let me tell you what I have learned.
It helps to buy quality the first time. If you don't, your wife will be frustrated with her machine and she won't know if it's because she isn't any good or doesn't like sewing or if it's the machine. Lower quality machines may not sew straight, the stitch quality isn't as good, it may have tension problems, etc.
You definitely want to get a machine that comes with lessons. If you buy one from a dealer, they will not necessarily teach her how to *construct* something but they will teach her how to use each of the feet, how to thread, oil and clean fuzz out of the machine, that sort of thing.
There are many brands that people like and are loyal to. You should make a decision based on what is available in your area. I like my Bernina but if I had to travel 100 miles the Bernina dealer, I may have rather had a Pfaff.
My parents got me a Kenmore to practice on. I loved sewing. I hated that machine. I wanted to chuck out the window when it would nest up (the thread would loop on the bottom and get caught around the bobbin) so badly it would tear through my fabric and ruin my project.
I bought myself (what I now know to be) an overpriced $600 Brother. It had all the features - auto needle up and down, push button thread cutter, embroidery.... but it refuses to sew in a straight line or sew through more than 4 layers of fabric. It would just stop and not sew any more, if I gave it what any other machine would fly right through. It is happy as an embroidery machine, but not as a sewing machine.
Finally, I got a Bernina 230. The 3 series Berninas just came out to replace these, so they are on sale right now. I think mine was around $800. It does NOT have all the bells and whistles. For that, in a Bernina, you must spends thousands. However, despite needing to cut my own thread, it does *everything* I ask it to do. Sewing is a dream. I've used it every day for a year now, just sent it in for service and it came back better-than-new.
My first two machines, in the end, cost more than my new machine.
If you see that $800 and cringe, I would recommend finding a good, new-ish (3-5 years old) used machine. Many quilters trade up for a larger machine (to make larger quilts), and they take loving care of their machines. You can find these for sale, sometimes even at the dealer (because they take trade-ins). Also keep in mind that if you wife ends up hating sewing, a quality machine is going to have a decent resale value. Also, sometimes buying a sewing machine from a dealer is like buying a car. It's hard to find out what the "MSRP" is so you should call different dealers and try to pin down a price. Sometimes they will throw in extra feet or extra lessons to get the sale. Give the place closest to you (assuming they are nice) the best opportunity to make the sale, since they will be the ones performing the service. I just got my first year of cleaning for free.
Thank you for doing your research first, because it will make a huge difference in her experience!