The short answer is no, it is not worth it. With a similar amount of money you can make a good PPC compaign.
Well, there should be no short answers for questions such as this. For most people on DP, who look to make a quick buck with a quick turn around rather than the long-term operation of a reputable site, Yahoo Directory listings are worthless as they generate fewer and fewer traffic everyday.
I would submit a free listing and forget about it, just like DMOZ. Ranking well in the Yahoo search engine isn't too difficult, so focus on that. Infact, focus on ranking well in Google and the rest will follow.