rebel_son,
50 Yards = 45.72 Meters so you're well within the 100 meter distance limitation.
I'm not sure you can actually BUY a pre-made CAT5 or CAT6 cable of that length but they're NOT hard to make if you have the bulk wire, RJ45 connectors and a crimping tool.
OR, you can go to:
http://www.cablewholesale.com/specs/10x8-02150.htm
and purchase a 60 foot CAT6 cable (better than CAT5) for $15.13 plus shipping & handling.
- John