Neighbor problems

Kayli
So I believe a pattern is starting to arise and it worries me. The neighbor across the street is very strange to put it in the nicest way. He sits in his mini van all day and most of the night just watching the other neighbors. Recently, he has taken a fancy to my husband. My husband is a very kind person and goes out of his way to help people but I feel like this man is abusing my husbands kind personality. 
A few weeks ago he showed up at the front door asking for money to put gas into his car because he was out. He is a 50 year old man! We are college students with a baby on the way. I just feel like it's totally inappropriate to be asking neighbors you barely know for money. 
A few days later he asked for my husbands number. He has called him every day since then for favors. Also my husband was being nice to the guy because he had said its his birthday and told him he would possibly buy him something. The guy went on to tell him exactly what he wanted. He then came over a few days later to remind him to buy him his birthday present. I have finally talked to my husband and told him to be careful what he is saying to this man because he is taking advantage of him! 
Today he shows up at my house and is now asking me to drive his wife around! I don't even know her!  I try to be a good neighbor but I like my space and hate feeling like I can't go outside without this man asking for something else.
What do we do? I want to just tell him that we do not have time for all of his favors we have own lives to worry about. But how do you say this without being rude? He is watching my house in a mini van everyday and it freaks me out! I want this to end before our little guys gets here.