We had also had issues with Huggies and other brands of diapers not fitting well and leaking all over. Pee on guests and poop on yourself at 2 a.m. need to be avoided. The only brand that seemed to work perfectly was Pampers Sensitive. (As the boys got older their skin was not quite as sensitive, and we gradually switched to Kirkland diapers and wipes.) To try to keep costs down I did a lot of ordering on Diapers.com. They have a user-friendly site, quick shipping, and accept coupons! And ordering in bulk helped keep costs down a fraction. Amazon also has several options for money-saving ordering (such as Amazon Mom). I also know a lot of moms who are coupon geniuses, and can manage name-brand diapers from Walgreens or CVS for less than even Costco.
If you are still having issues with rashes, you could consider making your own, all-natural wipes. A friend of mine does this for her child (recipe below) and here is what she has to say: