calculation not accurate

發帖費 ： 0.15 * 0.8 = 0.12
成交費 ： 0.35 * 0.8 = 0.27 (eBay fee discount)
paypal 費用 ： 0.42 (based on 3%, should be 1.9%) at $0.38 (Paypal volume discount at 1.9% for > 100K/month).

mail: $0.5-0.8 (use first class no tracking), count probability of loss ($0.6 - $1 saving in mail is worth the risk in statistics).

cost of good: $1

Total: $2.27 - $2.5, profit: $1.5/item

Feedback 50K/month, transaction: 50K X 5 = 250K

Net profit/month = $375K

transaction per day 8-9K

# of employees: 15 - 20. salary: $50-60K.

profit after labor: $300K/month