You have 10 years until the merchant appears, so there are multiple options on how to reach the goal, but here's how I did it:

- Start as King of Greed with 3 points spent in "Nepo-Baby" (King's abilities)
- Don't use any cards that spend or gain money (including cards that buff your units like Midas touch, vaults, etc.)
- Don't throw any card in the pit
- You can build units, towers etc. as usual. Upgrades you can also choose preferably level ups for your units/towers to make them stronger to do the fights for you.
- Each year/round gives you +9 Gold after the round is over.
- Kill 8 golden units in these 10 years with your palace (1 Gold per golden unit killed for Palace Level 1, 2 Gold for Palace Level 2, so you have to kill either 8 units or 4 units depends if you level the palace). Otherwise just sit back and let your units do the rest, don't accidentally kill more golden units than needed.
- When year 10 starts you will be presented with one last choice of cards, that's the point where you burn all your money to come out with 29 Gold. After the choice of cards, the merchant will appear directly and the achievement pops up.

Note: You decide when to kill the 8 golden units with your palace Level 1, you can do multiple in one year or kill 1 each year, up to you. I counted the money for these 8 units at the end-year below.

- Year 1: 60 startgold +9 for year = 69
- Year 2: +30 startgold +9 = 108
- Year 3: +9 = 117
- Year 4: +9 = 126
- Year 5: +9 = 135
- Year 6: +9 = 144
- Year 7: +9 = 153
- Year 8: +9 = 162
- Year 9: +9 = 171
- Year 10: +8 from the killcount = 179, then re-roll 5 times (-10, -20, -30, -40, -50) = 29 Gold

Hope this helped and enjoy your achievement. :)