Shovel Knight: Treasure Trove

After defeating the first House of Joustus and boarding the Glidewing, head to the upper level of the ship to find Gouache, the artist. He will agree to paint you for 1,500 gold. After time passes and you continue playing the game, speaking to him again will prompt him to ask for more money for more supplies, which will then cost more as he continues to improve the painting. He only asks for money to continue his painting two times before the achievement will pop, but it can be further revised if that is your desire.