Postby jemstone » November 5th, 2007 10:35 am
your idea is correct. ただ is "just" while だけ is "only".
ただ is more like "just" with the meaning of "recently". i suppose that's why you say ただいま when you step into your house or someone else's, like saying "i've just stepped into your house."
だけ is more like "only" with the meaning of "limited". for the phrase すこしだけ means "a little only". though in english we can say "just a little" but the meaning of "just" here is more like "only" where it sends the message of "limited".
so in an example, if you say "just 2 dollars!", that is an example of だけ because it's "only 2 dollars".