Depends on if you really need regulated or not, if you don't, any old wall wart around your acceptable input range will do. If you need regulated the 5V SMPS from a cell phone charger like device is perfect, all you need is a cap right at the device and you're all set, if it's cheaper you could pick a wall wart with a high enough overhead and use a linear regulator, but I prefer the SMPS one's myself, all the works done, and I get family members that give me one or two a month.