Diono Radian RXT- Check out cheeky cherubs or ebay. I got mine for just under $400 including freight. It is newborn(rf for up to 4yrs) to 10yrs. It has tether strap or isofix or both if you want. Its an awesome slim line seat and it feels rock solid in the car. Steel frame and memory foam which makes it super comfy for your child. Highly recommend this seat!