I visited Stonehenge (and its sister site, Avebury) in May 2017 after the new carpark and visitor's centre were opened. The car park is now about one mile distant from the actual stones, and you need to get a shuttle bus from the visitor's centre to the site. The buses are quite regular so the system works pretty well.
Given the expensive price, many people will tell you that you can just look over the fence from the next field for free, and they're right. However, I wouldn't recommend this since: a) you can only see it from one angle, ticket holders can see from 360 degrees at varying angles, and b) you won't really get a clear view since there will always be people in front of you.
With that said, I think Avebury is probably a better and more interesting site than Stonehenge. Not quite as impressive, but the circle is bigger and you can still interact with the stones (at Stonehenge you're now about 3 metres away at the closest point).