That depends on what you consider a "low-priced" item. Here's a breakdown of how much you keep from an eBay sale:
Final Price / eBay fee / Your profit / Profit %
$1 / 35¢ / 65¢ / 65%
$3 / 46¢ / $2.54 / 85%
$5 / 56¢ / $4.44 / 89%
$10 / 83¢ / $9.18 / 92%
$20 / $1.35 / $18.65 / 93%
$40 / $2.03 / $37.98 / 95%
You can see that the more the item sells for, the greater percentage you keep. But anything over $5 is worth it to me. Actually, I sell junk for $3, just to get rid of it. Who cares that it costs me 15% for the opportunity to find a buyer. Otherwise, I'm stuck with it, and get $0.