As much as I would agree with avoiding printing.com where possible, I do know that their scratch cards are half price until the end of Jan, about £440 for 10000. Doesn't seem tooooo bad (for them anyway).£199 for 5000
It's a simple enough job. As a bespoke order though you would struggle to beat 5000 for £199 as in the real world you have one four colour setup, a screen printing setup and bit of trimming and delivery. I would be close to this, but probably the wrong side of £199.
Of course though as a stand alone job there are other benefits as it's simple enough to run more than one design, you can run whatever size you want (even different sizes) and variable text isn't an impossibility.