Dont sound too bad. The Tacamo AK and M4 faux mag kits are $50 US. Which would probably a bit more in Canada since your dollars are worth a little more then US dollars currently I believe. (Havent checked the exchange rate in six months or better.)
I was thinking the Metadyne mag kit for the A5 was showing $60 or so on Rockstar, so if they do one for the 98, it'd be around that. Sounds like the one you found is probbaly a darn good deal for a mag.