I'm pretty sure the Good vs. Evil edition is $20 at Circuit City, because it was $10 a few months ago during their 50% off PC games sale. It doesn't show up on the website, though.
Another thing you can try is just finding one game separately. When the publisher fully acquired the property a few months back, they gave everyone access to the other game at no cost. Both games have been pennied out individually at Gamestop/EB, so you might want to check there.
The game is great, but it's from before World of Warcraft, so it is dated. You can seldom solo or even duo, and playing with a team is absolutely necessary. Thankfully, CoX has the best community of any online game I've seen, and most people would be glad to help you out if needed.
Have you tried Guild Wars? They're all cheap, there's no monthly fees, and it is more or less an MMO, minus the persistent world. There's also Tabula Rasa if you demand immediate satisfaction from your games, though there's no longevity to it.