Given that there are many competing platforms out there in the 'open source' community, I would argue the opposite - many of DNN modules and skins are overpriced for what you get.
Sure, there are modules that worth a premium (ActiveModules' and DataSprings come to mind), but I bought more than my fair share of garbage modules that did not worth 'right out of the box' as advertised, were not CSS/XHTML compliant and returned dozen of validation errors, and required lots of tweaking to make them look and feel like they were integrated in the site, etc, etc, etc. I feel embarrassed to have bought a $49 ajax 'accordion' module to dress up the lackluster FAQ module on my site, given that the code used was found with a few Google searches (but I lack the requisite programming skills to wrap this into a module).
I am surprised with the number of skins that are developed and sold for more than $50-$75/per and STILL are produce dozens of WC3 errors (realizing, of course, that DNN ships failing validation).
I recently joined a template club for another platform ($75) and have dozens and dozens of beautiful strict XHTML templates that are done in pure CSS w/o tables...about the price I paid for my first DNN skin that, still today, has 70+ errors. I've had to buy one $60 module for this other platform that does what the $80 module I bought in the DNN world could not do on its own (and with dozens of errors and months of SQL tweaks and SP needed to fire it right). I've also joined a module club ($50) that has some amazing modules that, if purchased equivalents on SnowCovered, would have run me upwards of $1000 (and sure to have errors and problems that need addressing). Each of these modules worked flawlessly "out of the box."
Perhaps the old adage no longer holds - rarely do you get what you pay for on Snowcovered. Mandeeps tabs come to mind...Worse $50 I ever spent. (I downloaded an animated bouncing Yahoo-tabs module that is amazing for the other platform...free, of course...and, as you might have guessed worked perfectly "out-of-the-box."
What say you?