HMI + PLC in one combination

[rupej]

The older series Unitronics (Samba, Vision, etc) are probably the cheapest decent thing out there that meets your requirements. That said, they aren't without their quirks and don't seem quite as reliable as most PLCs.

The newer series Unitronics (Unistream) are very modern and are a good option IMO.

 

[Rson]

I would just get a Click PLC + Automation Direct HMI.

You can expand if you ever need to. You get around 8DI 6 DO, and you can get those in analog varieties as well. The HMI will go into a panel I'm guessing, and the footprint of a click PLC behind it isn't that big of a deal.

Get the power supply on it and you can wire a 120V plug and go directly into the wall.