Is there something your hometown is known for? I am kicking around the idea of mini bottles of Frank's hot sauce with a chicken wing chocolate tied to it.
My family has a cottage where I spent every summer while growing up. Local to the cottage is a family farm that makes maple syrup and my FI and I go through the stuff like crazy. I originally wanted to get married at my family's cottage but it wasn't really feasible so as our favours we're planning on giving a small bottle of the local syrup per couple. It's about $7 per bottle but our guest list is under 40 so it's not so bad. It's a way to bring a bit of the cottage into the wedding and still have something edible, but personal. We're also big fans of supporting local or family run businesses, so it works for us on all counts.
This is a great idea since it is personal, and ties into the location/what's special to the couple. If you can find something like this, that would be great. I don't take knick-knack favors with me anymore. If I can't use it up, it's just another thing to put in a junk drawer or throw away. Like other posters said, I don't want or need any form of "john loves jane" shot glass, koozie, etc. I love things I can use up, think fondly of the person who gave it to me, then be done with--the maple syrup is a perfect example of this. I'm also pretty over anything that looks like a kid's craft project. I respect that DIY saves a lot of money, but if it looks like a DIY craft project, I really don't want to take it with me.
The reality is that you can't give everyone a favor they'll love. Prepare yourself to not have hurt feelings if whatever it is gets left behind. Also, sometimes people leave things behind unintentionally. At a friend's wedding, the place cards were mini champagne bottles with gift tags attached. I got up to dance and mingle, and forgot to go back for my mini bottle. When I got home that night, I was really sad because I'd totally have made it into a mimosa the next morning.
Re: Favor help