What an interesting question! Bard's immediate reward for killing Smaug, the dragon, is the freedom of Dale, his city. However, forthcoming events transpire which allow Bard the ability to restore both Dale and Laketown to their former glories.
To recap, immediately after Smaug's death, the men of Laketown clamor to make Bard king of Esgaroth (or Laketown). However, the Master of Laketown isn't too keen on this development. He argues that Laketown has always "elected masters from among the old and wise, and have not endured the rule of mere fighting men." Bard moves on, but he eventually meets with Thorin to bargain for part of the treasure Smaug had hoarded when he was alive.
Bard reasons that since Smaug had stolen much of the wealth from Dale, the people of Dale deserve some part of the treasure that the dwarves now claim for themselves. At this point, Bard also speaks up for the people of Laketown, whose city was destroyed by the dragon. Bard's position is that both the people of Dale and Laketown could use some of the treasure to rebuild their cities and their lives. More importantly, since he was the one who killed Smaug, Bard wants a twelfth of the treasure; for his part, Thorin Oakenshield, the leader of the dwarves, isn't too eager to share his hoard of gold and silver.
Things change, however, when Bilbo hands over to Bard the Arkenstone of Thrain, an heirloom of Thorin's house. With the Arkenstone in his possession, Bard is able to force a bargain from Thorin. In exchange for the Arkenstone, Thorin will give Bard a fourteenth share of the hoard in silver and gold.
It is this fourteenth share of the treasure that Bard uses to rebuild both Laketown and Dale. So, you can say that, after he kills the dragon, Bard is richly rewarded. First, his city is freed from assaults by Smaug. Second, his own act of courage gives him the leverage to bargain for part of the treasure the dwarves have laid claim to. With his fourteenth share of the treasure, Bard is not only able to help Laketown rebuild, he is also able to return Dale to its former splendor. Additionally, his reputation grows so well that men from the Lake and other areas look to him as their new leader.