budget digital interconnect

any recommendations for a cheapo digital cable for a second, budget system? (for that matter, is the difference between a digital coax cable and a RCA just the shielding?)
BLUEJEANSCABLE.COM has some excellent reasonably priced products that are made-to-order; and service is terrific. I ordered a digital cable this morning and it was shipped by noon the same day via Priority Mail.
supposedly, although a regular old rca cable will carry a digital signal, it has a different impedance and/or looser tolerances than a specially-designed digital coax cable and thus will experience more signal degradation. on the other hand, digital coax and video composite cables are both designed to have the same characteristic impedance (i think 75ohm) and should perform the same. i'm sure the cable acolytes out there can point out some major differences, but i can't hear any.
to which end, i use garden-variety belden or acoustic research digital coax cables, which you can get for ten bucks or less at parts express or amazon.
Canare makes a decent budget 75 ohm cable at well under $50 and it's as low as I would go--that or Apogee Wyde Eye. Make sure you get a 1.5m length. If you can go up a smidge to about $150, the Atlas Compass is a good one, or a VH Audio cryo Pulsar.
thanks all - lots of great ideas and helpful info.
I meant really cheap - and Loomis' suggestions ($10) are what I was hoping to hear of.
Second Hifixpert's suggestion of the Bluejeanscable digital cables. Great build quality and sound with exceptional service. Their Belden 1694A-based cable is $16 for a 3' length.
Virtue Audio is an unusualy good value I've discovered.
I've had both their copper and silver digital ic's. Very impressive.
Go to HAVE Digital. They have some really nice Canare options for about 50 bucks. Sounds smooth as silk.