Need Inexpensive Digital Cable

Black Cat Veloce.  They were $123 new...

Try Acoustic Research , I use them on my Theta gear. They replaced my Wonderlink with no quality drop off.

Not sure what you mean by "inexpensive", but a couple of very affordable, well engineered cables are those by Blue Jeans Cables and Cable Solutions.  The Blue Jeans cables are made with Belden cable and use Canare RCA connectors.  They run about $18 for 5 feet.  The Cable Solutions cables use Canare wire and RCA connectors. They run about $41 for 1.5 M.  The Canare RCA connectors are an important part of these cables since these connectors are closer to a 75 ohm impedance than the typical RCA connector.  Like all audiophile wire there are lots of opinions on what makes a good cable, but I replaced a 0.5 M Kimber AGDL with a 5 foot Blue Jeans and it sounds better.  The Kimber used ultra plate RCA connectors and was not an optimal length (1.5 M supposedly), so that may explain the improvement.   Good luck!

1+ for Blue Jeans cable. Strict 75 Ohm. It is said that cables between .5 meters and 1.5 meters are better. Well made. Affordable. Durable. 

Cables longer than 1.5m (or shorter than 1 foot) are better.  Best would be 1.5-2m
Digital cable is system dependent.  Cable that works great in one system might sound poor in another.