Yeah, TOTW1 is usually a very good investment in general, as it is even more supply limited than any other TOTW as the fewest packs were opened when they were available. TOTW2 is still supply limited, but like NML said, there are more packs being opened during this time so they aren't as rare as you might think. With Week2 IFs it is often best to wait until they stabilize in price after they are completely out of packs (during Week 3). For the rest of the year they should go up (unless the player gets a 2nd IF). A lot of the huge SBCs that come later require IFs as well, and some of those challenges seemed to drive up prices on ALL the IFs, even the ones nobody wants to play with.
Week 3 TOTW is when you get to the normal pattern of hitting a low point sometime Sunday night-Tuesday after they are released but while they are still in packs. Sunday night reward packs increase the supply and people selling after using the player over the weekend increase the supply, etc. If you buy in this period and hold for a couple of weeks the supply on the market begins to dwindle and prices increase.
Now any time you can buy an IF for right at discard value (122 X the OVR rating for Gold IFs, ie an 82 OVR player sells for 122X82 = 10,004). When I say "discard value" I mean either buying that player for 10,000 coins (or more usually the next increment up 10,250 coins, which means you are still buying him for less than the Quick Sell + the value of his contracts). The reason the quicksell/discard needs to be considered is it can help you get your money back without worrying about having to make a profit on the player after tax (The EA tax is 5%, which is significant at this price range). If you buy a player for 10,250 you would have to sell him for 11,000 to make a profit after the EA tax. Selling him for 10,250 would actually net you only 9,737 coins after tax.
This is why people listing their players for such low starting bids are dumb, they could have ended up with more money in their account by just quick selling them. Never list for less than 1.05 x the quick sell value! Whatever, we take advantage of these dum dums and buy IFs for discard value because we can really never lose on a player like this. At worst, we play him through his contract quick sell him. Generally 7 contracts is worth about 300 gameplay coins created (assuming at worst 500 coins per match /11 players = 45 coins per player/match x 7 contracts per player = $315 coins value in 7 contracts) and a lot more when you still have coin boosts going. So even if you pay 10,250 for a player with a quick sell value of 10,004 you've created net value for your club just by using him and quick selling. If the player does go up in value, then you can actually sell him for a profit. Also, it is just plain fun to use IFs, especially when it costs you nothing!