This seems to be more a function anachronistic copyright law more than anything else. In modern society, documents are constantly scanned and the ease of reselling electronic materials--as opposed to physical materials---is a central part of commerce.
There is a false distinction being made here that somehow enables people to morally condemn individuals for engaging in activities that even this site supports (albeit in an ever so slightly different form).
There is no way at this point you can believe what you are doing could possibly be legal. I assume you are clinging to your failing argument to avoid admission to yourself. So I'm going to attempt to give an analogy that will hopefully register with you.
If you go into a retailer and purchase a paper copy of a book, you are entitled to that copy and you are free to sell
that copy to a secondhand buyer. But if you take that copy, duplicate it, and then go to the bookstore and sell the copy, you have violated the law. No matter where you try to sell it, it is illegal. You violated the law upon duplication. This is no different than the person who buys a movie, duplicates it in bulk, and then sells the copies on a downtown street corner. They are selling stolen goods.
What is completely legal, and encouraged by BR, is the selling of the actual books once you are done with them. That helps a buyer of the books to recoup some of their costs, which is a good thing if someone is strapped for cash. Given the way the market works with resale prices, they can get back nearly all of what they spent. So in essence, the current system helps the struggling student quite nicely.
When you come along and buy a stolen copy from a criminal, you deny the company that made the book and the authors of that book, money they worked for. But I have gathered from this thread that is irrelevant to you. But that's not the only person you screwed over. The person who is struggling to get by each month who obeyed the law and bought the books full price with the intention to sell them now has to compete with a criminal giving away stolen materials for free. Your criminal actions are hurting the very person you are claiming to care about, because the people who might have bought their used copy legally are now getting illegal copies from you.
You have dropped a few diatribes here about how you are doing all this to help the poor and needy, but in reality you are only helping yourself. You have claimed to not care about the money and that your intentions are purely good. Yet when I offered you a great way to help those need, pay what you should have paid, and live up to your claims of not caring about the money, you completely ignored the offer. It still stands.
If you can show that you donated $250 (the difference between what you paid for a stolen copy and what you should have paid new) to a needy organization, argument is over. Also, if you want to buy a needy group (such as the students in a state-augmented postbacc program) a full set of new books (or even a used set from an SDN seller), BR will send a second set to that group for free. You have the opportunity to live up to the words you have typed in this thread. It's completely up to you whether you want to keep up this charade of buying stolen goods under the auspices of helping the poor or whether you actually want to help them.