I bought most of my materials on Ebay and I'm sure I did save money overall. However, in retrospect I'm not sure it was worth the hassle. The reasonably up-to-date books tend to go at perhaps half-price after you've included postage, so if you can get a package that saves significantly on the RRP then you may get some shiny new books and equipment without paying all that much more.
If I was to do it all over again, I would have bought a nice headset early on, with active noise reduction.