Here is the full list of all 20 World of Retailing achievements.
Enter the World of Retailing
Become a millionaire
Talk to 15 NPC's
Sell atleast 10 products
Be a victim of theft
Sell atleast 10 products to the same customer
Talk to a VIP
Try to ripfoff someone
Sell 100 products
Talk to 10 VIP's
Talk to 100 VIP's
Own every shop in the town
Sell 200 products
Sell 500 products
Sell 1000 products
Watch the credits till the end
Talk to 50 NPC's
Talk to 100 NPC's
Talk to 200 NPC's
Buy atleast 100 products