> In Europe you get about 1000kWh a year from 1000kW of solar panel

Typo, 1000kWh from 1kW of solar panel.

I got my 4x 455W panels for 70€ each from BayWa (random vendor in Germany), plus delivery. Microinverter ~200€. Aluminium etc for installation ~400€ or so. I installed them together with a friend. Total cost ~900€ or so. At 30ct/kWh in Germany, break even is in 3 years. Would be earlier if I had a better roof to put them on, mine has some shadow.