I did it myself for an older Jeep Cherokee and it was a breeze. The newer cars need you to fake the signals that come from the chips mounted in the key, and all sorts of other over complicated BS.
Everything you need is available. The problems that you'll encounter are documented on forums somewhere. It definitely CAN be done, but it's such a PITA that it's simply worth it to pay.
Even though Best Buy has an air of incompetence, it's a good choice, because they are a national chain with deep pockets. If they damage the vehicle you have recourse. They understand this, and it forces them to train people well enough to not damage vehicles.
I bought a nifty unit that has all sorts of stupid features I don't use; like telling me the temp inside the car. All you need it to do is start the car and work the door locks. Ignore upgrades.
I try not to get wrapped up in silly things that make us soft, but we really appreciate the remote start in WI winters. Your fuel bill will go up a few greenbacks, but your wife will know you cherish her.