It was only a matter of time before Copa starting selling miles!
So, it seems that the standard rate is USD30 per thousand, although you can get them for USD20/1,000 with 50% bonus miles by buying 50,000 during the current promo. According to the T&Cs, the maximum mile purchase per transaction is 50,000 and the maximum miles that can be purchased in a single calendar year is 100,000. This doesn't appear to include bonus miles.
To determine whether it's worth buying any miles, we need to look at redemptions. Generally speaking their award chart seems to resemble that of United. Aust-Europe redemptions are identical in price. The Australia-South Asia award zone seems interesting. South Asia includes Singapore, Thailand, Hong Kong and Bangladesh. A one-way flight in J costs 30K miles, and F costs 40K miles. By taking advantage of the 50% bonus miles, that's effectively USD600 for J or USD800 for F to most of Asia.
I also notice that you get up to 2 open jaws and 1 stopover for free on round-trip awards.
It looks like you can book online too, although it seems a bit clunky. Only direct flights seem to show online, and you can only search one day at a time.