The amd CPUs are not very great cpus at all. If they need to browse the internet and use MS office they are ok, but even then you will notice the difference.
The quad core wont make much of any difference unless they are doing applications that will take advantage of multiple cores, and if they are using higher end programs like that then those amd cpus are going to be horrible.
As for as office that depends on what you need. The student version of office with word/excel/power point you can get for $100 per computer. If you need outlook or access or publisher or any premium one, espcally on 3 or more systems, then you might look at the office 365 subscription with is full office pro for $100 per year for 5 devices.