Though I play mostly unpowered Vintage and Legacy, and thus what I have to say doesn't apply too much to Standard, I will suggest that you just bite the bullet and buy as many of the staple cards as you can, even if they're really expensive. Things like Wrath of God will continue to be reprinted for ages, and they're good in a lot of white decks. Dual lands are also a solid investment. The painlands in Tenth Edition are a good starting place, as they're Standard-legal, and beyond those, albeit not in Standard, there are the Ravnica "shocklands" (such as Godless Shrine) and the original duals (such as Scrubland). If you're playing a lot of black, the Torment tainted lands are solid cards. Ultimately, it comes down to whatever you can find people playing, and the older the format, the longer-lived your purchases will be. You should also try to find large, bulk sets of commons and uncommons for relatively cheap, because that gives you a wide range of workhorses for whatever decks you might want to try.
Also, try to settle into which colour(s) you like the most (for example, I personally never play blue or green) as early on as you can, as that'll cut down the costs significantly, over trying to buy staples for every colour.
PS, ignore metricus. Magic is by far and wide superior to Yu-Gi-Oh in every possible respect.