It may be true that you value not killing a random person more than literally more liquid value than all of humanity can produce, but I doubt it. In any case, we know from observation that plenty of people do in fact kill random people for substantially less than everything.
If instead it is suggested, as Phyllo does, that one might prefer to die than to kill an innocent, it only entails that that person values their own continued existence less than they value the life of the other (or rather, the moral belief that they shouldn’t kill).
Let’s put it differently: Take Singer’s parable of the drowning child. How much do you sacrifice to save the drowning child? Put differently, how much do you currently contribute to charitable causes that demonstrably save the lives on innocents for around a thousand dollars? If the amount you currently donate to those causes is zero, you probably aren’t as committed to not killing people as you claim. Moreover, if you currently choose to buy yourself food instead of contributing every cent you earn to saving those lives until you die from hunger and exhaustion, you probably aren’t so strongly committed to dying rather than killing.
It may be that you just aren’t a consequentialist, and you base your morality in the opinion of some all loving god who could care less about what happens to anyone around you so long as you don’t participate directly in the causal chain that leads to their death. That morality is nonsense for a number of reasons, but that is a different discussion and my argument here doesn’t address it.
On the other hand, it may just be that the idea of accepting money in exchange for committing moral wrongs is seen as taboo. That’s understandable, because signaling a commitment to moral positions that is strong enough to overcome any personal gain is important for social cohesion and alliance building.
Here is one test: if you think that it’s right to pull the lever in the trolley problem, to save five lives by killing one, then why would it be the case that you can’t accept $10,000 to kill a random person and then donate that money to a charitable initiative that reliably saves a life for each $1,000 it receives? You would on net save 9 lives, 5 lives better than in the trolley problem. What gives? We’re just replacing the trolley switch with a check for killing the one person followed by an alms collection to save the five.
Here’s another way to approach the problem, which is probably where we should have started: I think lying is always wrong, but surely you would tell a white lie for $1 million, right? Think of all the orphans you could save! Murder is an extreme case, and when we start there it’s easy to take our gut rejection as an indication that there’s nothing to this price-of-morality argument. But start with tiny moral wrongs, and (I hope) it’s clear that we would take money for small moral wrongs. If nothing else, we can differentiate moral wrongs for which it’s not taboo to discuss accepting money to violate, and ones for which it is.