Need help transferring data from a serial device to a PC and outputting it in Ex

I hope this is the right forum to ask such a question as I can't seem to find a category to classify this with.

Basically, I'm working through my college course on a project outside the college that simulates a real world water treatment plant. A serial device, located on the processes, is used to collect data, like water pressure, temperature, etc.

I need a way to transfer the information from the serial device, which is basically just a plug on an older machine (I really don't know the specifics on this device, but it's basically just a box with a serial port), to a PC and somehow output this data in a program like Excel.

Another problem I have, is that there is no budget for the overall program. After hours of research on the topic, the only solution I've come across is ByteWedge, which basically does everything i mentioned. The problem is, it's $149 USD.

I have the null modem cable needed to create the physical link, I am however lacking a means of collecting and organizing the data on the PC.

If anybody knows of a free program similar in features to ByteWedge (http://www.bytewedge.com/) or another way to get this to work, please, help me! Any help on this topic will be appreciated.

Again, I'm sorry if I posted this on the wrong board!