Need advice

I’m getting into collecting again for the first time since I was 10 years old, and I was thinking about investing in a really nice card that I can potentially flip in a year or two. I’m looking to spend roughly $500-$700 max. But every time I go to EBay to look for a card to buy, it just seems so daunting because there are sooo many variations of cards for each player. I also can’t decide which player to invest in. I was thinking about a prospect like Roman Anthony.

So my questions are this: 1. How do I choose which player to invest in? And 2. Once I decide on the player, how do I choose which card to purchase? I know I should be checking for recently sold cards to see if I’m getting a good deal or not, so other than that…

Thanks in advance!