Just because something is more experience doesn't necessarily mean it's safe. However, buying cheap isn't always the best way to go either. Yes, there are options in between both price point ranges yet many have issues, recalls, negative feedback, etc.
Further, I know definitely that, as much as I love to bargain hunt and secure finds at yards sales, consignment stores, Good Will, and other places, car seats are not a product that should be bought second hand no matter how much you think it looks like it's in good condition. When you don't know a car seat's history you are gambling with your child's life. However, if you have the option to be loaned or given a car seat by someone you know and; therefore, know the history of the car seat, and confirm that it has not been inside a vehicle where any minor or major incidents occurred, only then might you consider a second hand option.