I use godaddy for my domain registration and pay the extra bit for privacy.
My domain expires next year and I'd like to renew but was wondering if there was anything cheaper since it's like $20/year basically ($10/domain, $10/privacy).
Also, if you login, add the renewal to your cart, and then leave (without purchasing), they will generally send you a promo code via email a few days later to entice you.
The other option is to renew for more than 1 year at a time if you are planning on keeping to domain for an extended period of time.