Bing Lee on eBay are selling Microsoft Family 365 for $111, less $10 if you use code MCPAY10.
Confirmed on purchase and after applying Microsoft Office voucher to my account that an additional 3 months is added to the 12 months purchased. The image in the email also shows +3 months in the top right, which isn't actually advertised. I basically got 15 months for $101, or $6.73 per month, making it around $1.15 per user per month. Equivalent 12 month price is $80.80.
As a result, I will be buying another 12 (+3) months to stack on top.
If memory serves, you only get the 3 months on a new account. If you already have an account it will only be 12 months.