If you are capable of tying knots, I would suggest you try making your own. Mind you, there are good ropes to use, and bad ones, but if you do it right, you can make them cheap and great.

You can find instructions for the Prussic knot on the internet. For the larger rope, I went to cheaperthandirt.com. They sell/sold lengths of climbing rope at cheap prices. They were just the ends that were left over from other mountaineering companies, but they will work just fine. I then went to EMS.com and bought the smaller diameter rope for the prusic knot. Once I had everything, I made my own. Don't quote me on this, but I think I made 9 or 10 for under 50 bucks.

I believe you need some type of rope called kernmantle, but again, this was a few years ago and I don't remember for sure. You need to buy the mountain rope for sure though, not the cheap plastic rope that most stores sell.

There was an entire article in a magazine either last year or two. I think it was in Field and Stream, not positive though. I'll look for it, and I'll post it for you if I find it. Maybe somebody else knows exactly what you need.