If you're looking to play StarCraft online later this year, it looks like Blizzard is going to make you pick up StarCraft: Remastered if you're interested in using either Matchmaking or Ladder features.
The first StarCraft is still excellent but the sequel is high on our list of the Best Strategy Games on PC. Why don’t you have a look what else is on there?
According to Blizzard on a post at the official Blizzard forums, previously Matchmaking and Ladder features were going to be free for both StarCraft: Remastered and StarCraft Anthology players. Unfortunately the decision was made after the position became "untenable" during playtesting and other development-related events.
That said, both features will now be available to those who purchase StarCraft: Remastered, as Blizzard state this will be the "best way to preserve the integrity of the play experience." So if you were looking to get some multiplayer in without coughing up the dough, you might want to change your plan up a bit.