I guess there are a few questions here.
You state you are looking for a new machine. Do you mean a brand new server latest generation etc? Or just new to you server?
What type of specs are you looking for $100 budget is quite decent for something such as an E3 or similar type of spec.
Most companies should have something in place to block NTP attacks for you already using at the least some type of filters on their routers or ddos protection.