I would buy a 30-06. There are are plenty on the market and you can buy reduced recoil ammo.
I know this will stir up a new controversy among the "ballistic technicians" here but I don't mind.
First, the notion that there is plenty of "30-06 out there".
So is plenty of cheap stocks. There is a very good reason for it. People are switching to more "comfortable to shoot" calibers.
The other suggestion about 115gr. or "reduced recoil" in 30-06 is pretty crappy to suggest to a beginer. 30-06 as any other caliber has a designated best BC and best sectional density in certain weight of the bullet. That is the one that gets the best ballistics. 115gr is a far cry from the 168gr that is close to a perfect marriage for this caliber.
There is very, very few 30-06 rifles out there that shoot real tight groups with a varmint loads at 150 yards, since very few barrels like them.
So the notion of recommending to a beginner to spend money on a gun that will not even come close to either .243Win or 25-06Rem in accuracy and wide ammo availability is beyond my comprehension.