one man's trash is another man's treasure

• one man's meat is another man's poison
• one man's loss is another man's gain

One early use is in Hector Urquhart's Popular Tales of the West Highlands (1860s) where he wrote "one man's rubbish may be another's treasure".

one man's trash is another man's treasure

1. What is useless to one person is valuable to another.

• there's no accounting for taste