concessional
/ˌkɒnsɛsˈɪʊnəl, -sɪʊ-/Definitions
1. adjective
relating to or given as a concession, concessionary, or concessionally
“The government decided to implement concessional rates for low-income families to help them with their housing costs.”
2. noun
a concession, especially one granted under certain conditions
“The company offered a concessional rate to long-term customers to encourage them to stay with the service.”