Something like these with thermal liner removed so your jeans act as the liner? Halvarssons W Pant Waterproof Textile Trousers Black Hi-Art CE Level 2 Armour
ETA just seen your budget; but I picked a pair of Halvarssons trousers up a year or two ago in the sale for around the budget you have so it may be worth hunting around for sales once you see something you like.