Consider the price for a good firearm to be an investment. Some guns are WAAAAY overpriced because of market pressures (most M-16 lookalikes and real colt ARs) but some cost a lot because they're simply good guns. The K-22 is one of those that is probably worth it as an investment. My Mom got my Dad his K-22 over 30 years ago, and it's as reliable as it ever was, and shoots as straight today as it ever did. The K-22 is probably a bit overbuilt but that's on purpose.
I'd say find the right gun and save up until you can afford it. I've never made a gun purchase decision based on price alone, except when there was outright gouging going on (like with the ARs), and I think it's a reasonable policy to follow.
You may be able to find a K-22 used at a respectable gun dealer... Look for one with the original bluing and no rust. Check the condition of the adjustable rear sight too. I like the factory grip but feel free to experiment with grips to fit your hand.
If you go with the taurus, I just hope you don't end up trading it in for the gun you really wanted

Save some aggravation and get the right gun the first time. See if you can find some to shoot before buying, since that's the BEST way to decide. Buy the gun that feels best when actually shooting and holding it, not just what fits what is in reality just an arbitrary price range you set. If necessary, save your beer/pizza money for an extra month or two. A good gun will hold it's value and give back the purchase price in enjoyment many times over.
$390 spread over 30 years of ownership... That's what, 13 bucks a year, or $1.08 per month? That's less than one lost beer per month over 30 years. Get the gun you WANT

If thats the taurus then get it, but I really recommend trying them out first and buying the one that you like shooting better.