Hi Misty,
If money is no problem, whatever paper you want also can. My mum did the cards for me and as she is a designer, we could chose the card material from lots of paper samples that she has. And commercial printers should be able to score and fold the cards for you.
But for cards and envelopes, it is always the more you order then the cheaper per card. Some people even order envelopes made out of similar paper as the card and it can be made according to whatever size you want. So decide on your budget per card and envelope.