Agile tracks the wholesale prices of electricity, so it can go really high when heavy demand is predicted. You could make a lot if you have batteries by charging them fully during a dip in prices, then dumping the whole lot during a peak. With the Agile Import prices you very occasionally get times when the cost goes below zero - that's the time to charge your car and batteries fully and heat as much water as you can as you get paid to use it.
I'm on Octopus Flux, which is aimed at people with solar and batteries. It gives three fixed rates during the day. Export for me is 7.43p/kWh 02:00-05:00, 32.01p/kWh 16:00-19:00 and 19.72p/kWh the rest of the time. You need to have the matching Flux Import tariff to get Flux Export. Import rates are 11p/kWh higher than the Export rates, so 18.43p/kWh 02:00-05:00, 43.01p/kWh 16:00-19:00 and 30.72p/kWh the rest of the time.
Prices vary slightly by region.