So...making money out of TF2

You don't, not really. The people that do make it by tricking the idiots who hope to make money.

You gain items.
You craft 3 items into Scrap Metal
You craft 3 Scrap Metal into Reclaimed Metal
You then craft 3 Reclaimed Metal into Refined Metal and sell it.

Also if you get a rare drop you can try selling that too.

You can also pre-order some games and sell the TF2 items if it comes with the pre-order if you don't want them.

Edit: There's probably more. Not that much into TF2

I have made a few bucks just by selling the drops I get on CS:GO on the market. In tf2 you usually have to trade items for slightly more expensive items for a few days before you see any significant returns. Or you could do it like I do: hold on to a handful of items you know will increase in price and watch them rise.

How does it work? Trading. Luck. Sometimes, stupid people.
There're lot of aspects that influence "making money" from TF. But it requires one thing - time. Lots of time. Time is money and TF isn't worth your time. You'd have to invest months to see some results and some actual money.

it doesn't work anymore .

You don't make money out of TF2 unless you own about 500 idle accounts, bot on the steam market, or scam the shit out of people.

It's a game. Play it.

Get a real job, TF pays about 50 cents an hour.

I did make 2k in 2 years. Expend it all on games. Don't do it, it's a life eater. For the record, I don't have any idle accounts.

Some months ago, I thought making money out of TF2 is a very clever thing. Then I got a (part time) job.

I can write about Dota's trading (it has a similar base). So, if you want to be the "pro trader", you should sell your confidence. It is usual when "pro" make his keys by deseption. There are a lot of ways... If you want to be the fair trader, you should know that you will never become TF's rich man... But there are two ways: you should sell your life to TF or find a really unique method.

Open chests, get Unusuals, profit