I'm wondering if it would be cheaper to melt down wedding rings, or to have them resized?

My mom-in-law has given us her wedding rings from her previous marriages. She's been married 2x's & is no longer married. Her rings are tiny! I'm wondering if it would be cheaper to re-size one of the rings, or possibly having them melted down & made into a ring for the groom? We're trying to do our wedding as 'cheap' as possible, & my mother has said she has a wedding ring we can use that was my grandmother's. That one will probably have to be re-sized, also, but then we're still left to figure out the groom's ring...Any help would be greatly appreciated. & I am planning on speaking to a jeweler, but I probably can't until later in the week, so was just looking for some thoughts :)