Decathlon for me too! I've got a running waterproof from there and the sleeves zip off which is great for the slightly-cold but not freezing weather!
I'm a skint runner so I have what I consider to be the minimum - a warm hat (cold ears when running is bad!!), a baseball cap style hat (Decathlon, £3) thin gloves (same place, about £3) which are enough when I set off and thin enough to tuck down my tights when I've warmed up, a pair of ronhill tights, and a long seeved top. If it's really cold I just double up my running tops - I've got a sleeveless one, a t-shirt style one and a long sleeved one (all Decathlon for about a fiver each) and I just layer them according to the weather. Easy!
I don't really understand why anyone spends a fortune on branded running stuff - it just gets repeatedly sweaty and washed and then eventually binned. The only thing I spend money on is my shoes and socks.
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