I want to sell weapons for metal, how do I turn my weapons into scrap?

This is the weapons page. Click on the "Scrap Weapons" button to begin.

Here you choose the weapons you want to buy. I've selected a Tomislav and a Back Scratcher.
To the left you can filter your weapons if you for example only want to see Scout or Heavy weapons. 
To the right you'll see how many scraps you'll get for your weapons.
Hit the green "Trade Now!" button to continue

You're now in the queue to get your weapons scrapped. You can see the queue at the top of the screen. I'm currently in a "global queue" which is what you'll be in at the start. Then you'll be assigned to a bot to trade with it. You might be in a queue for a minute or so. 
You can see what the trade needs to look like. 1 scrap metal for my two weapons.

Now this will pop up. Click the green "Go to trade offer"

You'll now get into a trade. Simply accept the trade if everything is alright.
When the offer is alright and has gone through then the trade will be closed.

You'll now see this. You now have your metal. Simply close it by clicking the white X at the top right of the box.

You've now succesfully completed a weapons trade! Congratulations!
It's basically the same with all the other trades but you can always go and check those tutorials as well.

I want to buy weapons for metal, how do I buy weapons?

This is the weapons page. You can view a list of all available items at "Buy Weapons".

Here you can click on the weapons you want to buy and they'll appear at the top. For this example a Second Banana and a Lollichop were selected.
The filter button at the top-left allows you to filter the available weapons by class and/or slot, and the total price is displayed on the right.
If you would like to pay using just metal and keys, you can now hit the shopping cart icon to be added to the queue. If you would like to pay with your own weapons, you can instead press the inventory button and select the items you would like to pay with, after which you can press the shopping cart icon to get added to the queue.

Once you're in the queue you'll have to wait for the bot to send you the offer.

Once the bot has sent the offer, this popup will appear. To continue the trade, click on "Open Trade Offer" and the steam tradeoffer will appear.

Please check if the offer is correct, and then confirm and accept the trade. You will now have to confirm this trade within the steam authenticator.

Once you have confirmed the trade, the site should update shortly after. The items will now be available in your inventory. Congratulations on a successful trade!

This option automatically sells your duplicated weapons for metal so you don't have to slowly select one by one manually.

This option allows you to combine your metal without the need of opening the game.

You will have to wait until someone sells that specific item to the bot,as all of our bots are restocked by users like you.

You can also check the other banking types for your desired item (for example, if you are looking for rare hats or rare stranges, check out item banking)

Then you will have to wait until the bot gains more space by buying or selling (depending on what banking) items from/to the users. Staff will take action if it's needed, but we ask you to refrain from poking them about it every 5 minutes.

This happens when all of the bots from the banking which you are attempting to use are full, as we do not load the inventories of full bots in the general view. You will have to wait until they have more space in their inventory.