As mentioned previously, plenty of PC's can be had on a budget ($5-20). At $5-20 your margin for profit or loss are small. The occasional rarity with a known major leaguer can turn a small investment into a nice profit. My suggestion, just as in vintage baseball card collecting, would be focus to filter out the "noise".

What do you truly enjoy? For instance, sounds like Leon collects ballparks, I collect Washington semi-pro/minor league PC's; teams and fields from Central/Eastern Washington. If I wanted to collect PC's of the Ellensburg Rodeo I could buy 50 on fleabay right now, but narrowing the focus has kept my wallet on a chain so to speak. If I find 3 or 4 a year that fit my criteria I am happy. Best of luck on your new interest.