How many diapers should I get?
Depends on a number of factors (how often your baby goes, how often you change, how often you want to do laundry, how old your child is) but generally, 18-36. You will need more for younger babies, since they poop more often. I tended to wash every other day, and 24 diapers was plenty for my newborn. The longer the diaper sits in the diaper pail, the harder they are to clean. I suggest you get 18 to 24 diapers to start in a variety of styles in the beginning to see what works for you. Then you can purchase more of those that you like best.
What type of diapers work the best?
Some moms like the flexibility of prefolds. They can be used for a wide range of baby sizes. Whether your baby has wide or thin legs, thin or chunky belly, they can be easily adapted to the shape of the baby. You can pin them, use snappies (on some), stuff them in an AIO, or lay them in a cover. They dry quickly and can be used multiple purposes (burp cloths or cleaning rags when you are done diapering).
Fitted diapers are designed like disposable diapers in that they have fitted legs and either aplix or snaps to secure the diaper. Fitted diapers are much better at containing the more liquid-like poops of a newborn. They are great to use in the middle of the night when you can't really see what you are doing. They can be less intimidating for baby sitters or family members to learn to use. If your baby has extremely chunky or thin legs, you may have some problem getting fitted diapers that fit.
Contour diapers are a cross between prefolds and fitted. They have an hour glass cut so there is less bulk than a prefold but like a prefold you will need to use pins/snappies or lay them in a cover since there are no snaps or aplix. There is also no elastic in the legs so they do have the snug fit of a fitted. However, they will fit a wide variety of shapes and sizes.
Regardless of the type of diaper you choose, all of the diapers sold on this site will need a cover.
What do I need to use cloth diapers?
The basics: Cloth diapers, Covers, Pail with a lid, Wet bags.
How do I store dirty cloth diapers?
Line your pail with a wet bag. When you have a wet diaper, just toss it in. For diapers with poop on them, it depends. For newborns/breastfeed babies, just toss the diaper in the pail; for older kids with solid poop, dump the poop in the toiler first. Some folks dunk their poop diapers in the toilet, I found that this was an unnecessary and messy step. For wet bags, I recommend getting two that fit your pail and at least one small one for your diaper bag.
How do I wash cloth diapers?
When it is time to wash, you don't have to touch the diapers, just take the bag out of the pail, dump the diapers in the washer, and toss in the wet bag. I had bought a fancy washing machine that had an extra hot ?sanitizing' cycle but found I didn't need it, nor did I need to use hot. I found that washing on cold worked just fine to clean the diapers. For poop stains, the best thing you can do it hang them in the sunshine. You will be amazed. My two year old is no longer in diapers but for all the time he was none of our diapers have poop stains on them. Even if you can't hang them out all of the time, do it when you can. It helps. The sun also helps control smells.
Don't use fabric softener. It will reduce the absorbency of your diapers.
What is the cost comparison for cloth vs. disposables?
This will vary based on so many factors but to give you an idea, I searched the web for some calculations of costs.
The average child will remain in diapers for 2 ½ years, although many remain in diapers until they are 3 to 4 years old. There is some indication that because disposables do such a good job at keeping a child from feeling wetness, that those children using disposables tend to stay in diapers longer because they don't actually feel wet when they wet. But to try to compare apples to apples, all the numbers included here are based on 2 ½ years.
The Diaper Shop (http://www.diapershop.com/index.php/action/dollars/) has detailed calculations for the number of diapers your child will use over 2 ½ years and gives the cost of disposables for this period as $2184. They also give a detailed break down of the cost of washing cloth diapers at home and project that it will cost just over $400 over 2 ½ years. According to different accounts on the web you could spend anywhere from $350 to $1500 on cloth diapers/covers, depending on the type and number of cloth diapers/covers that you purchased. Based on these numbers, regardless of your choice of cloth diapers, you save using cloth diapers. Since you can use the cloth diapers for multiple children, the average cost for cloth diapers will go down if you use these cloth diapers for more than one child. Additionally, depending on ebay's rules at the time, you could sell them when you are finished using them and recoup some of your investment. Another good resource is the Diaper Pin which has a cost calculator (http://www.diaperpin.com/calculator/calculator.asp) that allows you to compare cloth diaper use with disposables based on the costs in your area.
These numbers are just estimates to give you an idea of costs. There are so many factors that are not included in these comparisons that can alter your actual costs (such as the cost of driving to get disposable diapers, the cost of disposable wipes, the variation in cost of disposables, the cost of cloth wipes, line drying vs. electric drier, purchasing used cloth diapers, diaper genie bags, etc) but these numbers can give you a good way to estimate your cost/saving.