ONLINE PRINTING: There's a pretty wide variety when it comes printing via online companies, so always make sure you can get a proof of your invitation. With some companies, that may cost extra, but it's usually not very much. Much like with at_home printing, your paper options will usually be limited to whatever the company carries, and each company's paper set is going to be slightly different. You can usually request paper samples for free. Here are a few companies I've used with good results:
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.