If there are a lot of you travelling, a cab becomes a pretty reasonable option price-wise and is much easier to time compared to a bus. Our taxis also have their own uniform, in Brighton colours!
The official colours of Brighton & Hove taxis is white and aqua (or teal, or torquoise, depending on how you want to label the colour) - these are the ones you'll see at taxi ranks and outside of the station.
There are also several private hire car companies, which can't wait in the taxi ranks, but can be booked over the phone. These don't have the same uniform as the taxi rank taxis.
The council sets the fares for taxis in Brighton, with a minimum of £2.80, climbing in 20p increments depending on distance. A rule of thumb is that the first mile costs about £4.60 (because of starting at £2.80) and each mile after that is about £2.20. If you hire a 5 to 8 passenger car, it is 50% more and it is also a bit more at night, on Sundays and on bank holidays. Each vehicle should display a fare card so you don't need to remember this! You can ask for a quote when booking, though these are typically estimates, so don't be surprised if it varies a bit.
01273 202020 and 01273 204060 are both commonly used numbers and really easy to remember, as is 01273 555555! There are plenty more though, so feel free to just hail one, pop to a rank or google "Brighton Taxis".