for love
Purely for one's pleasure or love for someone or something, rather than for money or another such benefit. A truly great player plays for love, not because a win might benefit his bank account the next day.
(just) for ˈlove/for the ˈlove of something
if you do something for love, you do it without payment or other reward, because you like the work or the person you are working for: She works in the museum during the summer but she doesn’t get paid. She helps for the love of it. for love
Out of compassion; with no thought for a reward: She volunteers at the hospital for love.