For households it depends on your contract with the energy companies. There are certain contracts which let you pay a fixed fee on top of market prices, but you'll move with hour by hour fluctuations of the market prices. This might be interesting for those with smart homes who can schedule many of the more energy intensive appliances to run when prices are at expected daily lows. Or because you generally dont use much power in the expensive moments for your region.

These contracts however also remove most of the protection you enjoy from price spikes due to technical failures in the grid, or errors in weather prediction for renewables.

For a couple of hours last week I was paid to use electricity. Price of eletricity goes negative fairly often, but only a little. On top of the electricity I, having a spot priced contract, pay a margin ~0.5 € cents/kWh and tax and transmission fee. Last two are about 3 cents /kWh. So for me to get paid the price has to be about -7¢/kWh and that has only ever happened during a few hours.