your morals are just fine
i see it a bit this way...
the (mis)spelling is incidental/irrelevant.
the issue is that: the seller knew what he was selling and he appears to be happy with the price he got, if not, he just made a mistake by not putting a (higher) reserve price on it.
in other words, if he was concerned that the price would ultimately be an issue, then a reserve would have been a smart move. he did not and hence the assumption is that he should be open to accept and be pleased with whatever is paid irregardless.
you were just lucky that there was a misspelling in the sense that, fewer buyers (perhaps) showed interest. who knows, maybe even with the correct spelling, you might not have paid more for it?
as far as your morals go... i think yours are stunning. and its HIGHLY COMMENDABLE of you.
you are obviously open to considering other peoples' situations, almost putting yourself in their shoes in an attempt to understand them. not many people do that. but don't get too carried away with the guilt aspect. a sign of respect is to also treat others as grownups by showing them that you respect their decisions and not try too look after them by second-guessing them unduly.
you are doing just fine according to me and you're doing some business as well. terrific!
