Offer them ten ! Seriously, you didn’t lose your key, you misplaced it . I lost mine recently and my wife found it for me. I put the key in the pocket of my riding jeans, rolled them up , and layer them on the shelf. Apparently the key fell out and went into a boot as I layed them down. I moved the boots, I moved the shelf, I looked on top of the boots. I didn’t shake the boots out. Have someone else look with a fresh perspective.
I've had a lost key like that. Getting ready to go on a long ride over Easter, went down town to do some shopping. Did as I usually did in those days, and dropped my bike keys into my helmet, along with my gloves.
Go off, and do the shopping I needed, get back to the bike, remove gloves from helmet, put on helmet, and realise - 'no keys...'. Remove helmet, go back to the shops I'd been in, scanning EVERY inch of footpath and shop floor. No keys. I remember that there is a Honda shop near(-ish - a couple of miles walk away). Call them - they have a box of old keys that I'm welcome to take and try (the bike at the time was a Honda CB750-4 F1). So I walk there, grab a large handful of keys, and walk back. About the third or fourth key did the trick (Honda locks back then were not very sophisticated), so I shoved the rest of the keys back into their bag, and pull on my helmet. As I went to pull on my gloves... Yup, there inside my gloves were the missing keys.

Rode back, and returned the rest of the keys to the shop, and purchased one of the ones that fitted, so as to have a spare in a different pocket...