You can find used hardware easily in many places like Ebay. However software is somewhat harder to find. Most programming software is licenced and therefore prople are not too quick to sell old copies.
In the way of new...Allen Bradley is offering a 10 point Micrologix with free programming software. This software is looks and works like all RSLogix software butit will only communicate with the 10 point Micrologix. Another option is Automation Direct. They offer low cost (for a PLC) hardware and software.
I was offered that Siemens kit (or one similar) not too long ago with a half day training class for $269. Check the local suppliers like AB, Siemens etc for seminars/classes with a plc kit included. This route may cost more and may not BUT it will also give you a connection to people that are familiar with and/or program plc's.
As was stated AB offers a 10 point Micrologix with free software for $99 but I think you still have to obtain or make a cable, it uses the 8 pin mini din cable 1761-CBL-PM02. This link will show you Micrologix: http://www.ab.com/plclogic/micrologix/
Fuji Electric offers a small plc (as low as $81) with free software. The cable is extra but I think you may be able to make one. You have to email them for a password to download the software but it only takes a day (at least for me thats all it took. http://www.fujielectric.com/distr/elc.htm
I cant leave our old friend Stephen out of this. Entertron sells plc's with free software. I am not sure of the pricing but I think it compares with most.
this is for the Crouzet Millenium II Micro PLC.
You can download the software for free. It is not ladder logic but graphical 'click and link' but it will teach you the principles for most apps. The software has a simulation feature that you can test your program with.
i'am new to plc's myself but i find it helpfull to use the zelio software that allows you to do small logic ladders and then simulate then to check if it works and it can also be used to see if a rung of the ladder is alright before using it in another software.
It is free to download from. www.schnieder.co.uk/software/zelio_soft.
hope you find this usefull