Where can I purchase new Key blanks?

I've been hangin on to older mopar keys,hoping they might be usefull one day.If you find a used key in good shape you could simply have the locksmith change the pins in the lock to match your "good" key. It's about a 10 minute job for a competent locksmith,if the cylinder is already out and accessable. It's also possible for a key to be mildly reground,and then the cylinder pins changed to match,as long as the key isnt totally worn out.