From SR4 page 303
QUOTE
The basic asking price for fenced gear is 30% of its original price. Fencing an item requires a Negotiation +
Charisma (10, 6 hours)
Other modifiers
Item stolen –20%
Item used –20%
Charisma (10, 6 hours)
Other modifiers
Item stolen –20%
Item used –20%
So, to sell a 1,000 item you would make 1,000*.3*.8*.8 = 192 on it (For Stolen and used and 30% reduction), with a 10 threshold and with a 8 Dicepool (most are lower) = 5 rolls (Buying success 1 for 4 dice)
19.2% of the items cost not bad.
You made 6.4

Makes most commlinks and standard weapons not worth the effort. You can added flooded market to standard low end commlinks and guns for another 2% overall loss.
Now lets add a Swag to the mix.
Connection 3 fence.... thats another 15% loss so....192*.85 = 163 but you don't have to spend the time...just go and do the drop.
Is 16.3% of an items cost worth the time to loot? Typically not, especially if the item is under 1,000 since the risk vs. reward should make you think twice.
Is this too far off form reality?