Depends on what an outage actually costs you. Two days without power in August means a freezer, a hotel, and a house at 95 degrees. If someone in the home runs medical equipment, or you cannot afford to lose a work day, the math is easy. If you can ride out 12 hours with a cooler, it may not be.
Two honest options. A portable with an interlock kit and a dedicated inlet runs the fridge, some lights and a window unit for a fraction of the cost, and you refuel it yourself. A standby unit sits on a pad, runs off the gas line, starts itself in about 10 seconds and needs nothing from you. If you already have natural gas at the home, the standby install is simpler than most people expect.
The part that is not optional either way is the transfer switch. Backfeeding a generator into a panel without one puts voltage on the utility line and can kill a lineman working your street. We will not install one without it.