If you're buying your own paper, you can find a good selection at local office shops when it comes to card stocks and glossy photo paper. However, if you're looking for linens or specialty papers, you may have to go online. Always get a sample before buying a huge stack of paper, and do a test print, to make sure that whoever or where ever you're printing from can actually use the paper you've selected with your design and medium. Here are a few other places to buy paper from.
RSVPS: Whether you choose to include a card for your guests to drop in the mail, a phone number to call, an email address to reply to, or a website to visit in order to collect your RSVPs, prepare yourself to have to hunt down more than a few people, regardless of your chosen method. We saved paper by only sending physical RSVP cards to our older guests (i.e., those who do not, and never will, own a computer or a smart phone) because we knew we'd have to chase down responses anyway. So we saved a little bit of money where we felt it might be thrown away otherwise. Here are a few more tips for collecting RSVPs.