I like rally games too, and first got into them at Dirt 3.
The Dirt series split into two games. Dirt Rally (and Dirt Rally 2), which tries hard to be a rally simulation. It is great, but quite difficult to learn and drive.
Then there is the original Dirt Series, which went on to Dirt 4 and Dirt 5. I haven't played Dirt 5, but Dirt 4 is a lot easier to drive than Dirt Rally. In the Dirt Series you tend to get more different vehicles and Dirt 4 has a stage generator.
I would have thought you could pick up Dirt 4 and Dirt Rally cheap as chips.
The WRC series I haven't really played since WRC4. People say it has come on a lot since then, it got up to WRC 10 I think, then the licence has now switched to Codemasters (makers of Dirt and Dirt Rally) which has been taken over by EA. They are releasing a new WRC title (which I assume will replace Dirt Rally) shortly.
Generally Dirt Rally 2 I think is the best. But as I said, it's hard and could be difficult to play if you are a novice and not willing to put the time in. But if you want to crash into verges then my guess is there will be a lot of that if you haven't played driving games for some time.
Oh yes, the original Dirt Rally (not 2) has Pikes Peak hillclimb in which is excellent.