We have multiple photovoltaic systems here at our little homestead. The primary DC system is designed specifically to run my amateur radio station, house lighting, and a small 12 VDC Dometic fridge/freezer. This primary system will not run the entire house, but it will run what I consider to be critical circuits, and the total cost was around $4000, and about half of the cost was due to lithium storage batteries.
Another DC photovoltaic system here is for a cabin, and it powers lighting, a ceiling fan, and another very small amateur radio station, the total cost for that system was $500-600.
In a past life, I designed, installed and maintained solar systems as part of my job. DC solar systems can be very simple, not expensive, and actually provide reliable power in a grid down situation. Look at some of the products from companies like Goal Zero and Renogy, they will help you plan your system. Solar photovoltaic systems are not rocket science. Be prepared!