Dueling is the fastest and the riskiest way to earn TC. Marketing requires effort for it to shine.

When you have very low TC, win some tourneys until you have around 5k. Now, start dueling if you are confident you can win. Your goal for starting marketing is 20k because a good percentage of items are available to be bought in the range of 20k. Marketing is much less riskier than dueling, but it is your call to choose which. If you play your cards right, you can walk out rich by both dueling and marketing.