I live in the PNW and always looking for a better solution. Not really bike specific, but typically use old Columbia gear after I wear it out from average use/commuting. A new up and coming company is Shower Pass. Generally gortex works the best, but hard to find a jacket under $250. Cheap route is layer up depending on temp and throw a shell on. Just my two cents. I am sure other will have some ideas. What is your general price range? What part of the country are you looking?
I'm actually looking for an allmountain style jacket....waterproof...not too hot (here the weather is really 'light' ... I found an alpinstars allmountain jacket at 40$. Too bad it sold out...for only 2-3 weeks of rain riding I'm not intended to spend more that 50$ Thank You
If you're not a fashion hound military goretex jackets and pants can be found on eBay. ECWS gen3 level 6 or something similar, single layers no insulation goretex is great. Can be found as cheap as $40 if you're willing to wait for the right auction.
Its light, packs small and the hoods are made for helmets if it really starts to pour.