Growing up, I had a friend whose father really got into collecting cards with him for a while. His dad actually bought about 5 or 6 Mantle cards as an investment (or at least that's what he probably told his wife). I remember going over this friend's house and being in absolute awe that he actually had a few of Mantle's Topps cards. Ever since then I've wanted one of my own. I picked this one up on Ebay a while back for a couple of reasons.
The card was a bit cheaper than most graded Mantle's since it's an All-Star card and not a regular base card, I think it set me back about $100 with shipping. Ironically, the fact that it's an All-Star card is the very reason I wanted it though. 1958 was the first year that Topps introduced All-Star cards, so it's kind of significant as far as the history of trading cards. I love the look of the All-Star cards from this year too, with the cropped photo of the player against a star-spangled background.
One of my collecting goals is to complete a PSA-graded 1958 Topps All-Star set. There were only 21 All-Star cards released altogether in '58 (#'s 475-495). I've already got 6 of them, and the Mantle was the most expensive, so I'm well on my way.