Waterproof jackets usually a rating of HH10000 or higher. I've for a Salomon Bonatti jacket but as long as you meeting the rating you'll be fine with most things. Smocks are often cheaper but I opted for a proper zipped jacket that I can get over me and my racing vest to keep my pack dry.
Decathlon, Ronhill, inov-8 all have their own versions
Target 38:00 10k, 18:00 5k