Making your own greetings cards...
(Sorry, Millie - I still think you might have a good idea - I'm just one of those cheapskates!)
Some people say it's tacky.
Some people say it's more personal.
You can use whatever language you want.
not that big a project?
There are some areas populated by huge numbers of Polish people.
Cornershops and the like might be a good place to start.