I just came across this in MSE, where it says that you can basicaly get a free DVD Player or a Hi -Fi when you open account with them and there is no minimum spend, so you can order for example some pens like ones bellow :
Y23-979537 - £1.59
Q51-S400-BK - 49p
To get this you should call 0844 579 0000 and quote the code Y23-PRDVD5 together with your order codes. There is also charge of £2.90 for p.p.
The thread was started yesterday at MSE, so I phoned Viking to ask is this offer still available and the answer was yes, and also confirmed that there is no minimum spend.