You might look at a thread I did on Miles Davis recordings, LP vs. CD. I compared Bitches Brew and Bags Groove CDs and Lps. Bottom line is, the more recent Blue Note remasterings are very good, either the Rudy van Gelder series or the 20 bit K2 series (which is related to the XRCD technology); the XRCDs can be good (but in my A-B of Bags Groove, came out second to the K2, though I really like the XRCD Bill Evans); and the newer Columbia remasterings of Miles Davis's material are very good. In fact, the best of the CDs gave the Lps a run for their money...they sounded different (somewhat), but not necessarily inferior. I did not find that to be true of the older Columbia CD of Bitches Brew (which I did not mention in the thread--it's really not very good).
I buy almost all of my jazz CDs on Amazon. There is a program on Amazon where you pay them a flat rate of something like $75.00/year and from then on don't pay postage (and what you get is second day delivery, I seem to recall). Since I'm a pretty serious CD addict, that's a very good deal...I don't have to order CDs in a bundle...I think of something I want, and just order it whenever I think of it. (Of course, that also explains part of why I order most of my CD's from Amazon...the other reason is because I like the access to customer reviews--and write some as well--plus there are usually interesting lists you can find that lead to new things to listen to).
Have a good time with it...
