Your first week will cost a little more than normal, since you may be buying things you may not have on hand (spices, cooking spray, etc.) You have to stock up on items. Because you will be cooking chicken a lot, we suggest buying boneless/skinless chicken breasts in bulk. In the weeks to follow, the expenses will decrease. The cost should be similar to your normal grocery store purchase, except it will be healthier! :)
Remember that your list is not set in stone. You can substitute to accommodate your favorite meals, or you can can eat the same meals two days in a row.