What to do if you receive a lot of replies to your ad
This is a good problem to have, but it can prove a little difficult!
It's not a bad idea to wait 24 hours after you've posted you ad before you decide who to give it to. That will give more people the opportunity to reply to your ad.
Of course, it is up to you how you decide. For example, you can choose the most polite answer; or the person who lives closest; or the person who has said something about what they are going to do with it; or some other criteria. But it is your choice and your decision is final.
It is worth making sure that the person you have offered it to actually turns up to collect it, before telling others that it is no longer available. But if you can, as a matter of courtesy, please try to respond to all enquiries and let people know that you have given it to someone else.