I get this question alot at daycare. First they say how cute the diapers are. Then they ask where you buy them.
There is one local store in my area that sells cloth diapers: Mama's Hip. Shannon is really nice - Caitlin and I went to New Mommy Group there when she was only about 5 weeks old. Her inventory on cloth diapers is pretty limited, though - I imagine it would be costly to keep a huge selection on hand.
The cheapest way to get your cloth diapers is (1) to find an online store that offers free shipping and wait for a sale, or (2) buy gently used diapers online.
There are several online retailers that offer free shipping. Sew Crafty Baby is my favorite. Jenn is very customer-service-oriented and does a great job. She had Thirsties drop-ship my new Duo Diaper to me and I got it before any other mamas had posted about it on Diaperswappers. I know that she had to pay them to do that, and she always offers free shipping on all orders, so I've gone back to her with subsequent orders.
She has a sale on Thirsties now. Wish I had my tax check in!
Buying FSOT has its advantages and disadvantages. I've had spurts where I've gone on FSOT binges. Then I buy things I regret and later sell them. I'll do a whole post on the game of selling on FSOT. The advantages to buying are: the seller pays the shipping and the fees. If they ask you to do that, it is against the forum rules and you should report them to a moderator. Or just move on and buy from someone else. Ask lots of questions or be prepared to get what you get if you don't. Ask about stains, what shape the elastic and velcro or snaps are in, if there is anything wonky about the diaper (like it was an irregular size or something wierd).
I use FSOT to get a new diaper I'm interested in trying without paying full price. Then if it works for your little one's build/size/shape, you can buy more feeling more comfortable about your decision.
It's hard that most of your cloth diaper purchases will have to be made without seeing the diaper before you pay. You can do research on the forums, but there's nothing like actually seeing the diaper in person to make a decision.
A number of mamas have started home based businesses making cloth diapers. They sell their wares on Diaperswappers, but also on sites like Etsy and HyenaCart. I love HC.
Check out this mama's store: BubuBebe. She is in Canada, and makes AWESOME diapers. Wee One's first birthday diaper is from her, as well as some other adorable fitteds I have gotten.
Another mama's diapers that I love: Nana's Bottoms. She makes great AIO's - she made Caitlin a preemie sized diaper in periwinkle blue to match her "coming home" outfit while I was on bedrest in the hospital. I loved it so much that I bought some more in newborn size, the pink one she wore in her first photo session!
Hyenacart and Etsy are also good sources for handmade woolies! All the woolies shown in my post on wool - except the ones I made, of course - are from Hyenacart stores.
Be careful - shopping for cloth diapers can become addictive!!!!!