Book prices are simply absurd. 30-40 a pop. Now let's put this into perspective:
You want to run a game. PHB, DMG, MM. 90-120 dollars + tax. Just the basics there.
Now as anyone here knows, most core only stuff isn't playable. You can certainly make a full caster (cleric/druid/sorcerer/wizard) work, and maybe a rogue or something. The rest? You need non core stuff. Say you want some variety, and not having a group that is Tier 1/Tier 1/Tier 5/Tier 5 or so. That third number may be off, I forget where Rogues were.
Again, 30-40 a pop. Say you want a Fighter that doesn't suck. Minimum CW, PHB2, ToB. Now we're at double cost.
Rogue? Add several more books. Ranger? Add a few more.
The cost easily gets well into the triple digit figures just to play what you want to play. Now, good luck justifying that cost on a cost/benefit analysis. It quickly starts getting to where you can just buy a console game system, an MMO, whatever save money, and still get entertained (provided you're into those things) with less hassle (as much as I enjoy D&D, you have to admit getting everyone on the same page to play is a hassle which is why tabletop sessions tend to be 1-2 times a week for a few hours each time as opposed to those options which are whenever you have a moment and want to, no setup time required).
This assumes all books are high quality. These days, most products made are actually low quality and are rarely worth the full (inflated) sticker price. Many of the books you'd need to play the character you want to play and not suck for example are rather lackluster. They just happen to have the right feats in them. Some however are quite good.
As a result... bittorrent for the win. I have a double digit GB figure of PDFs on my harddrive and no physical books for exactly this reason, and the fact I only play PbP anyways. If I found a tabletop game I might consider investing in used copies of the good books in a physical format for that purpose as then it would at least be somewhat justified. Of course, given that 4.0 is out, I have less than no interest in 4.0, and its existence means there will be an ever decreasing number of 3.5 games available the window has already passed.
Now compare to a computer game, namely Titan Quest. I was interested in this game, got the demo, played it through, but results were inconclusive. Now, Titan Quest is a computer game. As such, it is not available for rental, and once purchased cannot be refunded due ironically to that whole piracy thing. Between that, and the even lower quality of computer games on average it is necessary to ascertain the cost is worth the benefit before making it, otherwise it is yet another case of being ripped off by a shoddy product. If I knew someone else in my area that owned the game I could ask to borrow it for a few days and get a more extensive look at the game that way. The demo covers perhaps 1% of the game, this would give more like 5%. Being an 'RPG' (used loosely, still applies) that makes a big difference, as the beginning of said games is often different than the middle and end.
So I pirated it, got my test, and realized it got better from there. As such I purchased a physical copy of the game and its expansion and went from there. Were I not impressed with it, I would not have bought it. They lose nothing. I lose nothing.
The company that made it eventually went bankrupt due to the fact 75-90% of people playing it had pirated it due to a series of circumstances and had not done as I did and purchased a physical copy. I will say this though. If they had an official online thing that blocked pirated copies, they would have sold more due to the fact that'd force them to go buy it to play there. But it didn't, so nothing was lost. This is part of the reason why computer game quality is so low on average, though it is a chicken and egg type question. *shrugs*
