Saw this idea in a Q&A. Thought it was kind of interesting, although very unlikely to be in the game. Would be interesting to see "high demand" mechs cost more to repair and stuff that's underused becoming cheaper. It could be limited to something like 20% max fluctuation, so a 100,000 repair on the most popular chassis would become 120,000 while something less used would be 100,000 -> 80,000. Giving you a bonus for riding the unpopular mechs.
It wouldn't stop flavor of the months or popular chassis but it would give a little extra to players using less optimal chassis etc. It's not something I expect to see, but wanted to see what people thought.