Diapers and formula prices are on the rise, but a new blog could help you cut the cost. Tina Branch didn’t even realize it when Kimberly Clark and Proctor and Gamble raised prices by 7 percent on its Huggies and Pampers brand diapers. That's because she never pays full price anyway.   Now she's passing on her secrets on a new website, Baby Costcutters.com. Following the lead of other local coupon bloggers, Branch narrowed the focus of her site to only baby products--mainly diapers, formula and baby food. She launched the site in January and so far has about 80 followers.…