thanks to doubtful on MSE
The promotional packs are on offer for £3 in tesco
Buy a promotional pack of 10 BiC® Cristal® Medium Black pens between 1st April and 31st December 2010 and keep your receipt or invoice .
Use all the ink in your BiC® Cristal® Medium so that theres none visible in the cartridge, and the pen can no longer write.
Send Bic your pen! It's got to be at least 30 days after the date of purchase, but by 31st January 2011. Make sure you include the receipt or invoice, the completed application and the empty BiC® Cristal® Medium black promotional pack pouch 10 packaging too.
Theyll send you a cheque for £10 for each pen within 28 days. Only one claim per address. You need to register with the site to download an application form.
The website is http://www.challengebic.co.uk/