Unless the gifters are poor, AND have no idea of the value of the gift they have bestowed on you, It just sounds like they love you, understand your interests, and want you to be happy.

Problem?

If they really are poor, then sell the lot on eBay for maximum profits and take an agent's fee of 15% of the proceeds, and give them the rest. But since you're the one who who wastes his time mucking about with old bicycles, I'm guessing they're more well off than you.