How would I go about printing high-quality greeting cards at home?

It isn't the cheapest option, but if you're anything at all like me and the *slightest* mis-cut of a larger sheet of paper drives you mad, you should look at pre-scored card stock from someplace like http://www.paper-source.com/. I've run many many http://www.paper-source.com/cgi-bin/paper/envelopes/foldover.html through an HP deskjet printer and have always been happy with the results (my own wedding invitations included, though they were not foldover cards).

I've been very happy with http://www.redrivercatalog.com/cardshop/scored/index.htm greeting card inkjet paper.

This might be for fun or this might even be for a small side business, so any information would be appreciated.

Where I work, we send out a fair amount of cards and broshures. For the cards, we print a lot on the HP photo-smart c5180 (~$150). It's not the most ink-efficient thing in the world, but the quality really is pretty good. We also use it for printing photos, and while they're not the same quality as what we'd get developed at the store, the results more than suffice for showing off pictures inside the school. When we start doing larger quantities, we move up to the laser color printer. The thing you have to be wary of for LPs is that if you plan on using heavier paper (as I presume you would for cards), you start to run into issues with paper thickness (most LPs I've looked at max out around 160g/cm^2). We used an HP 2600n ($300), which was HP's cheapest color LP at the time. The quality is pretty good, but when you start doing bulk printing, particularly with cardstock, smearing and overall quality becomes a major issue. If you plan on trying to sell the cards, the results would have been unacceptable. At one point this year, we were printing a 7000-page project (uhg) and the printer sucked for it. Recently, we purchased a Brother DCP-9045CDN ($600), mainly because of duplex features and a 30-day return policy so I could test for smearing optioned we've encountered previously. So far, it's worked very well without any of the smearing issues from the 2600n. In the past, we've always got HPs at school, but I was pretty disappointed with the 2600n so I looked elsewhere. Whatever you decide on, I would check that the merchant has a good return policy so you can put the printer through the rigors to make sure it's quality is what you need. If you plan on using embossed paper for the cards, It's also important to note that printers can have major issues. Regarding printing by a pro, look in the yellow pages under printers. They do exactly what you're asking. Locally, color prints costs ~$0.30/pg, YMMV. The upfront cost of using a local printer is very low, but in the long run, it's cheaper to use your own supplies if you plan on doing significant printing and have the time. For instance, that 7000-pg project would have been $25000ish to print locally, and came up somewhere around $1200-$1500 to print in-house for ink and paper, and our ink cover was >75% on each page (a lot). There are cheaper alternatives online, but I've never tried them.

My friend swears by Costco online. My friend also swears by Vista Print online. I have seen some of his cards and they are great.

Photographer's Edge (http://photographersedge.com/) sells very nice blanks into which you stick (they're self adhesive with peel of strips) your own photos. I've used these very successfully in the past. Red River (http://www.redrivercatalog.com/) sells a complete "roll your own" solution where you print the cards, not just the photos. The site has a bunch of information on what printers work best, and have paper to match any card you might want to make.

after you've got them printed, i suggest a http://flickr.com/photos/zoopress_studio/857803295/ for scoring and getting a nice clean fold. also, if you're into typography, there are small http://www.briarpress.org/museum/browse?t=24 out there.

I'm not a designer or a printing expert, but I can tell a color laser print from ten feet away and it just doesn't look very good to me (for photographic images). A good inkjet print looks much better, but ink is expensive and prone to smearing. So if you can commit to a large quantity, I'd say go for online printing services. The minimums aren't too bad - generally around the 50 or 100 you were considering. I'd second snow joe's recommendation of http://www.vistaprint.com/ and I've also used http://www.overnightprints.com/ with good results. Most online printing companies will mail you samples of their work if you ask customer service. If you want to make small quantities of cards to test the market before you jump in to doing 100 at a time, even the cheapest inkjet printers do make beautiful prints these days. Look for a brand that claims water-resistant ink so it will be less likely to smear in a buyer's hands. A lot of photo printing services will print greeting cards for a few dollars each; I don't have any experience with those. They're either postcard style flat cards or photos pasted onto folded cards.

I do this occasionally for my wife using a standard bottom of the line, "free"-with-computer Epson inkjet (currently a Stylus C88+) and http://www.dickblick.com/zz119/15/ precut/pre-scored cards, which very handily include envelopes. I don't print anything on the inside, tho... I prep the artwork in PShop, then layout with back-matter and print the card in Illustrator; can't do bleeds. Can get at least 60 cards per $35 color-ink refill, often much more depending on the density of the design. They look great, but do take a while to dry; I have to individually remove them from the printed tray so that they don't stack and stick together, and then spread them out all over the room. She prefers the glossy stock; drying might not be such a problem with matte, but the ink usage might be higher. Probably not the best approach if you're anticipating regular runs of 100 and more.