How many cameras in total and how much does the whole system cost?
Bear in mind - this is in my home, not in my RV. Costs are rough numbers...
$100 to $1000 per camera depending on needs. Most of mine are $130 but I have one that is $600 (PTZ and powerful IR)
Most of my cameras are POE (power over Ethernet) - this requires a POE power supply. I use an 8-port 150 watt switch - $150
I think I spent maybe $600 on the computer plus another $150 for a Western Digital Purple HDD (note that I also use this computer as my home digital media server for music, movies, TV shows and pictures).
Then there's some infrastructure like Ethernet cabling, connectors, fasteners and misc. Figure maybe another $20 per camera for this.
Blue Iris is about $50
Hope this helps.