Kindlefeeder offers two types of service: free basic and premium.
Free basic: Just by having a Kindlefeeder user account, you can subscribe to up to 12 feeds and deliver these feeds to your Kindle from this website.
Premium: In addition to the features of free basic service, you can subscribe to an unlimited number of feeds and use a few extra service features.
Once you sign up and log in, you'll be able to see more details and upgrade to unlimited.
If you want to make a donation, please click here.