>>>i did learn aes and coax are not the same
True, AES uses what looks like a normal mic cable. Three pin XLR in each end. In the real world any standard mic cable can be used for AES, but if you want to run a long lenght (hundreds of feet), use a special cable. (By the way, AES stands for Audio Engineering Society. XLR is the Canon X series of connector, with a Latch and a Rubber ring).
>> is coax and spdif the same thing?
No.
Coax is cable technology. The word really is short for coaxial. In a coax cable there is in inner leader, isolation and an outer tube as the second leader. Hence the world coaxial, meaning both have the same axial.
spdif is short for Sony Philips Digital Interconnect Format. It is really a book describing how to do things.
There are several versions of spdif. The most common ones use optical cables. This version is often known as Toslink. (I think it was Toshiba that invented it).
The next most common version uses RCA connectors and a 75 ohm coaxial cable. (RCA by the way is Radio Corporation of America). The RCA connector was not really meant for this kind of usage, but it sort of works.
>>> then, whats a "good" coax cable to buy "reasonable" priced?
>>> finally, where can i get it?
To boil it all down, if you run a short cable with SPDIF you can use just about any cable. Digital sort of either works or not. If you get a sound it works, if all you get is pops and noise it is not good. Go to any radio shack, music store or low-end hifi store and ask for an SPDIF coax cable and they will suggest one at a reasonable price. Look for things like the length of the cable and if it looks able to withstand a bit of abuse. Avoid the high end audiophile shops, they will probably suggest a $3.000 cable as that makes them laugh all the way to the bank.
Gunnar