Your friend request/trade offer will be declined if you fail to meet these requirements.

You can either send a trade offer or do a normal trade.

Put up the exact amount if you want to use trade offers.
i.e., if my selling price for 2 tour of duty tickets + 1.00 ref is 1 key select the correct amount of metal to receive, otherwise the bot will decline the trade.
Bot will accept the trade if you fail to select your refined back.
Also, do not try to "buy" a ticket with the refined you get back from buying with keys. (it will get declined)
Note: if you pay with CS:GO keys your trade offer might get stuck. If it is not accepted within 2 minutes, cancel it and send it again.

Put up your metal/keys and say ready in the trade chat.
Alternatively, you can press the "ready to trade" button.

Use separate trade for buying and selling.
e.g., don't try to sell a team spirit and buy cream spirit in the same trade.

Bot trade chat commands:

ready - use this after you put up all your items; the bot will add the required items
r - same as ready

Exploiting bugs in this bot will not be without repercussions.

If the bot is out of stock you can use my dispenser.tf bot: http://dispenser.tf/wasda

Troubleshooting

1) If you send a friend request to the bot and receive the following message:

"This user's profile settings prevent you from contacting them at this time."
then you are marked a scammer on SteamRep and you are blocked from using the bot.

"Error adding friend. Please try again."
then you didn't meet the requirements for using this bot.
Please check your profile and inventory status.
To solve this error block and unblock the bot.

2) The trade times out a lot.

Check the Community/TF2 API status here: https://steamgaug.es/
If the either the Community or TF2 API is down you can try again later.
You can try to send a trade offer, if both are up.

3) Trade Offer errors

If you get an error 26 you should refresh the page. (the items you selected are already traded away)

For any other error:
Check your inventory capacity and the bots inventory capacity.
Log out and log back in.
Make sure you didn't trigger steam guard.
If this doesn't work you can try again later.

4) Bot is always busy

Trying to send a trade request results in "You cannot trade with Wasda because they are currently trading with someone else."
The bot has had a critical error and needs to be reset.
You can use my dispenser bot for the moment. http://dispenser.tf/wasda