I've discovered some simple brown cardboard cards at Kmart Australia that come with the cutest envelopes. A pack of 5 is only $3.50. Bargain!
I've been using them for all my "card required events" by personalising them according to what occasion and who I'm giving them to. To pretty up the front of the card I use whatever I can find like cut-outs from vintage books or those free postcards you find in cafes.
I also have a nifty little stash of lovely things I can stick on like buttons, old scrabble tiles and ink stamps to make them "pop" just a little bit more.
It only takes a quick moment and then you have a really lovely personalised card. It's also inexpensive which is a bonus.
If you're interested in making your own gift tags too, a friend has inspired me with her ingenious idea of using an old tissue box. To take a look, I've put the link here. I love a good upcycle idea!