OK, it's summer time and I saw some post people asking how to get to Brighton in a cheapish way!
Saw this on Daysoutguide website. You can use their whole network for weekends on a given day for £12.50, and it also includes using buses for unlimited on a given day!
All-inclusive off-peak day travel ticket for Southern trains in whole Southen Network and buses in South Downs area. Travel across the whole Southern network and South Downs area with Southern train services (including Crawley, Horsham, Redhill, East Croydon and London Victoria) and unlimited bus travel within the Downs area on bus services provided by Brighton and Hove, Cuckmere, Eastbourne and Rider.
Downlander e-tickets are sold exclusively online and cannot be bought at stations. Downlander comes in two types; the South Coast Downlander and All Network Downlander, both giving different ranges of travel.
Adult: £12.50, Child: £2.50.
See website above for more information.