You don't need a fancy generator. Any old cheap thing will do. A couple hundred for a used one, then a few hundred more for the electrical to wire it in properly. A manual transfer switch and a small sub panel. Running a house fridge from a solar system will be an expensive solar system. You need a lot of batteries and big inverter and then a lot of panels, if you need to recharge during the outage. You need to understand the loads and sizing.