We take our own photographs of local views, then print and sell them as mounted prints and greetings cards.
We use Photoshop CS5 and an Epson Stylus Photo A3+ R1900 8 Ink Printer.
For card stock we use 7" x 5" pre-scored 250gsm card from
www.vantagecrafts.co.uk who also do matching polybags and enevelopes.
You probably don't need to go to the extent of CS5 or the R1900 if you're just going to be doing greetings cards, Photoshop Elements would be much cheaper to start off with and you could find a cheaper but good A4 printer for the purpose. Just make sure it has individual ink cartridges for each colour which will give a better result than the 3-colours-in-one type of cartridge.
Printers never print out quite the same colours or vibrance as you see on screen, so be prepared to waste a bit of ink and card on trial and error settings to begin with.
We print directly on to the card, but I have seen similar cards done with a proper photo mounted onto the card stock.
We also do our own art cards, by means of using Photoshop and various graphic methods including (only commercially free) patterns, brushes, gradients and so on available on the internet. It depends on how deep you want to get into designing you're own cards but making use of these patterns and brushes can be real fun and inspiring if, like me, you're not an artist at heart.
We make sure our logo, contact details etc are also put on the back of each card.
Each polybagged card costs us about 38p excluding VAT to produce all in and we are able to sell these quite well at £1.99. I'm sure for personalisation you could bump this up a bit more.
Hope this helps for the time being - if you have anymore questions please just ask and I'll do my best to help.
