I would suggest downloading the free mod of the A-4E here: https://forums.eagle.ru/showthread.php?t=224989
It has a klickable cockpit, a load of weapons (including AGM-45 'Shrike') and it's really fun to fly. You can see in my signature what other aircraft I fly and I must say the A-4E is one of my favorites. Just try it. Won't cost you a dime. You can also find a good manual here: https://forums.eagle.ru/showthread.php?t=225016&page=5, post #42.
When you feel comfortable with the A-4E you can switch over to the A-10C, but don't do it without a HOTAS system. Else it will drive you nuts. :D
If you like it simple, take the A-10A.