How to set up a PLC for hobby home automation project?
For a cheaper solution you may use Chinese brand PLC FATEK, which you will get at very low price. You may also use Taiwan brand WINTEK HMI Touch Screen, You total cost will be under you limit. These products comes with Free Softwares, You may downloaded them from their websites for testing before purchasing.

You may use Microcontroller Development kit for this project, but for microcontroller development kit, high skills are required as compared to the PLC Project.

The main difference between Micro and PLC is of Graphical symbol programming and Monitoring, Programming of PLC is much simpler than of Microcontroller. And PLC has better online visual monitoring, however for Microcontroller monitoring you need to use JTAG.

AB Micrologix from plcdev are refurbished, and its Analog input/output card is costly. However FATEK comes with Digital and few Analog Input/outputs, so its depends upon requirements.

Another option is of SIEMENS LOGO PLC and Schneider Electric ZELIO PLC Smart Relay, its similar chinese product is IDEC SmarRelay. All these PLCs comes with a Graphical LCD, where you can see your data or any digital or analog I/O.

Among these PLC IDEC SmartRelays comes with four analog Inputs at lower price.

So, Choice is yours :)