Feel free to check my whole inventory. I don't accept coupons or discounts.
1:1
Same set (this game) trades. If you take one of my duplicate cards and give me a card that I don’t have yet.

1:1+1
Same set (this game) trades. You can choose any cards in my inventory and give me a card from the same set plus another item. The plus item is a compensation. Because after the trade, I will likely end up with duplicate cards or random cards, It doesn't help at all in my crafting badge process.
The plus item can be:
gems (25 or above)
steam emoji (marketable and tradeable)
steam background (marketable and tradeable)
another random card that you don't need anymore

1:2
Cross set trades, you can pick a card and give me any two cards with equal or higher market value.