SORRY IF POSTED ALREADY :)
Add SSFIV to your basket @ £16.99 (924/0799)
Add "Small Jewellery Box" To your basket @ £1.29 (237/0020)
You will notice that SSFIV has been reduced to £2.01
On the next screen you will notice SSFIV has gone back upto £16.99, click reserve after entering your email.
Check your emails, you have a total of £3.30.
Print it off and go collect lol.