So I am going to print my engagement party invitations via vista print. I have ordered quite a few things off there, including their postcards. I haven't ordered any invitations before, so I was wondering what people recommend to use? I can't order the sample kit, because that is only for US residents. I know the invitations are more expensive, because they usually only have 10 for free or a certain percentage off (I have a voucher for 30%) while postcards are regularly 100 for free. I probably need about 60. However, I did buy a living social voucher recently which gave me $70 worth of vista print credit (I paid $15) which doesn't cover shipping 
Anyway, what is the quality of the invitations like? I know there are a few options like linen, matt, and glossy - which one is better? Is it worth the extra money to buy invitations rather than postcards?
I know I should have just ordered 10 free invites with my last order (which I placed on FRIDAY) but that would have been intelligent
