If you're a dwarf, you might ask yourself, "Should I save the merchant? If I'm maxing Power is Money, I may not have the free cash to buy randarts."

Let's do the math to see how much gold is needed to keep Power is Money at full effectiveness through the ranks.

Rank 1: 85g per +1, +8 max: 680g
Rank 2: 78g per +1, +17 max: 1326g
Rank 3: 72g per +1, +24 max: 1728g
Rank 4: 68g per +1, +30 max: 2040g
Rank 5: 65g per +1, +35 max: 2275g

Not actually all that much given how much cash starts coming in during the second half of the game. So the answer is YES! Save that merchant. Just make sure to wait to buy randarts until you have at least 6275g and you'll be golden.