Varies as this is an umbrella term! Some brand names are Benzo Fury, Clockwork Orange, Vertex, Spice, Charlie White, Ivory Wave.
Legal to possess and use however the new Psychoactive Substances Act 2016, makes is illegal to produce stock or offer to supply or import psychoactive substances. Exemptions are those covered by the Misuse of Drugs Act. nicotine, alcohol, caffeine and medical products. If you buy online from an overseas website you could be committing an offence for importing psychoactive substances.
Varies due to wide variety available
Due to NPS being an umbrella term there are stimulant, depressant and hallucinogenic varieties.