The Davises have 300 Galleons in their vault, and they do not seem to be especially poor or especially wealthy. If Harry has 130 times the wealth of an average family, that sounds like a reasonable sum for the circumstances stated.

It's hard to compare, yes. But if you want to compare with the Davises and Potter fortunes, it doesn't sound like 40k is all that much.

For example, if we wanted to compare bounties, we could compare Voldemort to Osama bin Laden's federal bounty of $25 million; googling, the median net worth of an American household is something like $90,000, which gives us a Muggle multiplier of not 130x but 277x. If the Davises really are average (median) then with a Muggle multiplier the bounty on Voldemort might be as high as 113k galleons*. Then presumably you'd have the Potter family fortune of unknown thousands but let's round to 7k and then 120k total - that's 3 times what Harry actually has.

Of course, one can make assumptions which would erase a difference of 300% but you see why I might wonder if Harry did actually receive the bounties.

* Which if anything sounds low to me - Lucius shocks people by demanding 100k for Hermione just for attempting to kill Draco, but it seems plausible they would not be shocked by something like 10k - and Voldemort doesn't just attempt to kill one person, he kills dozens, hundreds, thousands, and multiple Noble House members. The Order, a subaltern organization unapproved of by Magical England, is able to raise 100k all on its own for its own operations. And so on.