I have had some Giclee prints and greetings cards printed by Picselation http://www.picselation.co.uk/ I can highly recommend them and although they don't have card prices on their website they are very reasonable and will do small quantities. About 64p each for 20 cards of the same 5"x7" image. You can have just a few printed if you wish but at an added cost. They will print whatever you require on the back and come individually packed with envelope ready to sell. Takes a lot of hassle out of doing it yourself and allows more time for painting.