Last year I engineered 2 systems for friends in Port St Lucie, and their 10kw systems only ran a little over $8,000 for DIY. It's even cheaper now. That was 10kw of mono PERC panels, an 8kw Fronius inverter, rails, L-feet, lag screws, sealant, AC disconnect, and all wiring. Both of them are A/C...