Looks like you need quite literally any prebuilt in your budget. Short of Planswift, it sounds like you could get away with a Raspberry Pi3. If your budget allows for it, something with an i5, 8GB of RAM, and a 1TB hdd would probably be more than enough. If it has a large SSD (240GB+) it would certainly feel faster and load programs quicker....but that's a budget thing.
9/8/16 at 1:59pm