The Tower carbon fiber paddle board is really nice and lightweight: https://www.towerpaddleboards.com/Carbon-Fiber-SUP-Paddle-by-Tower-p/pdl-twr-cf.htm
I wouldn't go with aluminum because they will wear you out faster... you'll notice it the more you paddle! Carbon fiber is always really nice and light, yet powerful. The Tower one is really great for that price too! It's usually around $300 for carbon fiber paddles.