Residency App. costs

Currently, the ERAS fee schedule is
$50 for USMLE transcript
$60 first 10 programs
$8/each #11-20
$15/each #21-30
$25/each thereafter

So 40 programs in one specialty would run $590. It gets cheaper but more complicated if you're applying to military programs or multiple specialties. More details at http://www.aamc.org/students/eras/feesbilling/start.htm

Travel and lodging costs really can be anything. Assume a per trip cost of $400 when flying ($200 plane ticket, $75 hotel, $75 rental car, $50 food & misc.) and $125 when driving ($75 hotel, $50 food & misc.) If your trips are split 50/50 flying and driving, they you would approach $6K total ($4000 + $1250 + $590.)
Of course, as you alluded, this will vary so wildly that hypotheticals don't mean much.

But ... this topic interests me. I'm surveying my 4th year classmates and hope to have data on actual spending by matchtime.