[Yoherz]

No no. You don't have to buy cards JUST to play me or yourself. In fact, I agree with you that it would be a waste of money since most MtG tournaments actually require you to buy a deck there and not open it until your first match.

If you're just coming out of YGO, then the closest thing you'll have is red cards. The next closest would be white or black, and then probably green.
Once you've played at least one deck of each color, you'll be able to have a good grasp on what color you're best with. Maybe buy one deck a month, depending on the price of cards where you live.
After you've tried out some of those decks, consider combining colors, like green/black, red/black. blue/green, or even the most common deck, which would be red/black.

Once you have your deck colors, you'll be doing great and you can simply tweak your deck and make it better, like I do.

If you want a suggestion for colors to try first, I'd say you're likely a green player. Maybe a green/black or red/black when mixed.
Also, black (and for the most part, white) is mainly a support color. I've yet to see a truly working pure black deck, and only one mostly working white deck that our state champion made and gave to me before he retired.