One should buy what one can afford. Right down to components and or enough ammo to have 1-5K. Depending if you're going to get in to LD / Precision , or have enough of what one feels comfortable with.

IMO any firearm (for personal use, PD, etc) should have a minimum of 1K per. You LD / Precision folks 1K is what , a good start

Also for the OP, remember what ever caliber you pick, it's only as good as the glass you put on it.