Just had this through by email and seems like a good deal! Ordered myself some free practice golf balls, came to under a fiver so completely free, didn't ask for any card details and don't even need to register. No minimum spend and free delivery. Gave this to a friend to try out and it seemed to work ok for him as well so it's obviously not just for subscribers to their newsletter.
Possibly 5% Quidco as well (although this does maybe seem a little bit cheeky!)
Just enter the code THEOPEN5 at checkout.
A good search to do in order to find some of the items (or maybe all) that are less than £5:
Website caught on, Minimum spend now £10