If you're trying to think of a way to get rid of the centerpieces afterwards, give them to grandmothers, mothers, special guests, etc to take home with them.
Favors are optional. People often expect them, but you don't have to give any out.
If you want to give away your centerpieces, I'd either give them to special people or make an announcement that guests may feel free to take home the centerpiece on their table.
Favors are your way of saying Thank you to your guests who have made it to celebrate your day with you. Although I do not think it is a requirement, I do believe it is a nice touch. There are several ways you can create low cost favors. If you dont want to bother doing them yourself, there are several places that offer favors that wont just get trashed by your guests (which would then be a huge waste of money). The candy bar is a nice treat also, but can sometimes be expensive. Private message me if you want to know who Im using to create mine. My friend used them and she had hers custom created. Good Luck!
Re: Favors
and no, you don't need to do wedding favors. They aren't a big deal and IMO a waste of time and money.
i did 3....one includes the candy buffet. but they are not needed.
Good Luck!