My favorite card site has three FREE Printable cards for Spring/Easter! Just add the ones you want to your cart. I had to enter my address but of course no payment info. Then you'll get an email with super easy download instructions.
I've used Letter Learning several times to get cards for my 4 yr old to give out.
They also have a few 12 card packs of Party Invitations for $2.99! Is it just me that likes my kid to do all work. :):)