I found the babywearing group on babycenter.com to be very helpful! Here is a message I copied giving advice about various kinds of carriers (sorry it's long)!
BTW, I plan to get a ring sling and either a woven wrap (not a Moby because I hear those only work for very young babies) or an Ergo. Hope it helps!
"If you don’t have a carrier and need some suggestions, continue reading.
Types of carriers
Wraps
Stretch wraps: A large piece of fabric that you wrap around you and your baby. Worn on the front only, no matter what the photos on other sites show. It is not safe as a back carrier.
Best for: newborns and up to about 18lbs
Not good for: heavier babies, back carries
Recommended brands: Sleepy Wrap, Wrapsody Bali Stretch, Lovey Duds
Not recommended: Moby because it is too thick, it sags and loosens, although many moms love these
DIY: YES and no sewing skill is required! Try these instructions here and here.
How to use the wrap
Woven Wraps: A woven piece of fabric that you wrap in various ways around you and your baby. This is different than a stretchy wrap because it is more supportive. There are about a million different ways to wrap these depending on the length of the wrap. Some wraps are thinner than others and I am even listing a gauze wrap brand that is great but these are more difficult to use.
Best for: babies of any size
Not recommended for: These are great for everyone who has the patience to learn how to use them. It is not that hard, I promise!
Recommended brands: Girasol, Didymos, Hoppediz, Storchenwiege, Neobulle, Ellaroo (thin-not for toddlers), Wrapsody Bali Breeze (gauze) , Vatanai (maker of the coveted Pamir hand woven wrap)
DIY?: You can make yourself a woven wrap using heavy gauze or osnaburg fabric but these fabrics will need to be hemmed and they will not be as good as the wraps suggested here. We don’t recommend DIY woven wraps.
How to use: There are hundreds of different ways to use these. Start with the instructions here: 1, 2, 3, and from SquishyMommy! (who has lots of different carrier videos!)
Mei Tai (MT)
A large rectangle of fabric with long straps that you tie on. Can be worn on the front or the back. Since it ties on it does not need to be sized. XL straps are available on many carriers.
Best for: Babies to toddlers
Not recommended for: Tiny newborns but only because it is not as easy to use as other newborn carriers. It is still safe though and many people use these with newborns.
Recommended brands: BabyHawk, Kozy, Freehand, Catbird Baby, Ball Baby Overall, there are lots and lots of good brands of these! Wrapstar is a new brand from our very own greytmommy! Stay tuned for more info on how to buy a Wrapstar.
Not recommended: Random ebay or etsy WAHM brands. Some brands really are great and we love the idea of supporting WAHMs. Many of the brands we recommend started out selling on ebay, etsy and Hyena Cart and some still do. Just do some research before buying one of these carriers. The Baby Wearer is a great place to check reviews but since many of these are so unknown, you might need to do a thread search or even a Google search to find more info or ask us for help. There are a few brands in particular that are well known for using inferior materials or shoddy workmanship which compromises the safety of the carrier. Just be careful.
How to use a mei tai: Instructions from Kozy, TBW, and Squishymommy
DIY: Yes but a moderate level of sewing skills is required. Select bottomweight fabrics including denim, canvas, twill and upholstery fabric only. Quilter’s cotton should only be used for accents, not the stability pieces of the carrier. Great tutorials are available from SBP, TBW and here.
Soft Structured Carrier (SSC)
This is a carrier similar to a mei tai but uses buckles instead of ties. These are super comfortable and can be used for front or back carries and these are especially good for heavy toddlers. Can be adjusted for different users. Very dad-friendly!
Best for: Babies to toddlers
Not good for: Difficult to fit very petite mamas
Recommended brands: Beco, Ergo, AngelPack, Pikkalo (the only one with facing out capability), Patapum, Olives and Applesauce, Dream Carriers, Two Mommas Designs (these last three also carry ½ buckle and mei tai carriers)
Not recommended: Baby Bjorn (this is in the category because it buckles on but this carrier is designed differently and is really inferior to the others)
DIY?: Yes, but it is important to find strong clips and webbing.
How to use a SSC
Comparison Chart
More info from TBW
Pouches
These are tubes of fabric that your fold in half and wear like a sash. Your baby fits into the pocket made by the fold. These must be correctly sized in order to work properly. These come padded and unpadded. I personally like the padded better.
Best for: Newborns who like the cradle hold, infants and toddlers in the hip carry. Good for quick trips.
Not good for: Long carries with a heavy baby, the period between about 4-6 months
Recommended brands: Hotslings, Peanut Shell, Karma Baby (these run large), Zolowear, Kangaroo Korner (adjustable)
Not recommended: New Native (hangs too low to be comfortable but some moms love it), ebay pouch slings (read the Not Recommended section under Mei Tais)
DIY?: Yes but it is difficult to find a pattern that fits. You are better off making a pattern from a pouch you know fits you. Here is one tutorial though. Be sure to read this on how to choose fabric.
How to use a pouch by PDF (with troubleshooting) and youtube.
Ring Slings
Carriers similar to pouches but with adjustable rings. These also come padded and unpadded but I prefer unpadded slings since they are easier to adjust.
Best for: newborns through toddlers, great for nursing
Not good for: some ring slings are not good for heavy toddlers, no back carries
Recommended brands: Sleeping Baby Productions (otherwise known as SBP, HIGHLY RECOMMENDED), Kalea Baby, Sakura Bloom, Zolowear
Not recommended: Again with the random ebay brands. I especially worry about the quality of fabric and the rings being used on these. You can’t beat SBP slings and they are just about the most affordable out there. Go with that instead!
DIY?: Absolutely and with minimal sewing skills required. Please order sling rings from here and read these instructions.
How to use a ring sling: I love the Zolowear videos. Here is a good one on how to nurse in a sling.
Places to buy
Used
The Baby Wearer: Must be a member (it’s free!) and to sell on the FSOT board, you must be a member for 30 days AND have 30 posts. This can be a little overwhelming at first. If you know what you want, we can help you navigate and search for your carrier.
Diaper Swappers: Must be a member (it’s free!) and there is no post minimum to sell. You do have to have 10 posts to add photos though. You will find the occasional crappy carrier here but there are lots of great deals here too.
BBC Babywearing Swap: must be approved to join the group. Pretty slow moving but still has good deals.
Ebay (do you really need a link?) Just be wary of non-name brand slings.
New
Slings I Love
Frogmama
Attached to Baby"