Do you need a monitor?
i5-4xxx (although not anything ending in a U as they are ultra low power and designed for ultra notebooks), 8-16G memory, 120+G SSD as a boot drive (you may have problems with this in your budget), xxTB as hard drive. Graphics card is unimportant. I'd use the integrated graphics on the i5 personally. Not bought a PC for years (build my own) but the usual suspects will be along to tell you best places to buy (e.g. Novatech etc...).