Not really. Dark Alakazam goes for about $2-$3. They were worth more back in the day when the set was around and when the Pokemon TCG was more popular.
The card with the most worth out of the Dark cards are going to be Dark Charizard and Dark Raichu. These two were the most popular back in the days, Charizard because it is a Charizard and Raichu because it was a Secret card. These two go for $11 max.
Dark and Light cards aren't worth anymore than regular cards. The Rocket sets (and Neo 4) included a number of Dark cards as the final evolutions for Pokemon. Light cards were equally used as final stages in Neo 4.