Cheap temporary audio system for Panasonic DMP-BD60

[Omix]

Hi to all,
I have purchased the Panasonic DMP-BD60 and now I am looking for a Audio System.

Right know I can not afford an expensive setup and I am thinking in the meanwhile to buy one of those 5.1 or 7.1 PC system to use in my Blu-ray.

As most of you know, the BD60 has only HDMI and Optical Audio Outs.

Any suggestion?

Thanks in advanced.

EDIT: Let´s throw a range price: $0 - $80
(I saw once in Amazon a Yamaha 5.1 Home T. in $69. Don´t remember if it has HDMI/Op. AUDIO OUT, so this is why I am expecting something less than $80)