NHL 15

EDIT 2: THIS ACHIEVEMENT IS POSSIBLE as of Sept 24, 2014.

Every week, EA Sports will usually update their Team of the Week that you can see in the menus, although right now the Team of The Week are regular cards, so this can't be achieved just yet.

Once the Team of the Week is updated, EA will put cards in packs that you can buy, or you can save up your coins and buy them on the market. Until the cards are released, there's no way to determine what their individual values will be, or which one will be cheapest.

When you get one, the achievement should theoretically pop. I'll update once the cards come out.

EDIT 1: In-game menu shows TOTW cards will start when hockey begins. That's in about 3.5 weeks from today (Sept 13)

At this point (May 2020), the auction house is pretty much dead. The plus side is that you can obtain these in any of the packs available in the store. Bronze, Silver, and Gold packs all have a chance of giving a Team of the Week item. The "Jumbo" packs seem to have slightly better odds of producing Team of the Week players.

The way I got this, and the easiest way in my opinion, is to log in every day and collect the free coins for doing so. Save up 2500 coins (the equivalent of 2 days of logging in with the maximum 7-day multiplier) and buy Bronze Jumbo packs. You can try with regular bronze packs, but the chances of Rare players are increased with the Jumbo packs.

For reference, I just opened 5 jumbo packs and got 2 Team of the Week players, so it shouldn't take too long. Of course, it's all luck based. Keep an eye on the auction house, too, as you never know when one will pop up.

The market and games in NHL 15 in ultimate team is really broken right now because no one's really playing it, but you're gonna want to get around 1.5k coins somehow and go to the marketplace, click buy, and set the searching to a team of the week player and there is usually one up for around 1.5k so you just grab that and the achievement is yours. I can't imagine people will still be playing this when NHL 17 comes out so get this while you can!