Just my two cents... The values of blessed RBs and ethies don't diverge too much from the standard plat/market rate. It would be rare to see someone selling either of these items for much less than face value unless the person was in a pinch for quick gold. Good luck.
I could see like a 100k or something price adjustment in some circumstances, but yeah, blessed rune books are a commodity that will always be desired pretty much. Same with ethies, though certain types of ethies may end up selling for a bit less than face value depending on people's taste.
I never said that 2.5 isn't a fair price, still I think it was worth a try to see if could find any for cheaper, prices sometime also goes with demand/offer. Anyway I disagree with that idea of "if you can afford 2mil, you can also afford 2.5" Some people have an hell of a lot of wealth, some other struggled to reach 2mil, I am the second kind.
I had been aiming to save 2.5 for a blessed runebook. I've now made 2.5 mil and I'm not going to buy one. Reason being - as nice as it would be to have the option of instantly travelling to one of 16 locations immediately upon resurrection - or the ability to bounce around, I've found that just having a few runes for a quiet bank where I can access ALL of my runebooks and going to bank first has saved me 2.5 million. Maybe one day when I have millions and millions in the bank I'll get one but right now, meh. Don't get me wrong - I'd love one - but I love having the money more right now.