I agree with you both. I think it really depends on "what" the module is. For instance I payed the $120.00 for the Game Zone module. But its also over 4400 games (2.2Gig) complete package with integration into Dolphin. Ability to interact with other members, battles, championships, etc. A lot of work involved in it, and worth the price.
However, if someone wanted to post a mod for a Facebook live feed module for $25-$30, knowing that ANYONE can get that widget for free from Facebook is really just trying to rip people off. The power is that you have the option to buy it or not. If you think the person is overcharging for their mod, simply move on to the next :)
Chris