This is a bit of a product review (unpaid and unsolicited), which is not something I typically do here, but some photo friends of mine have found informal versions of this on Facebook useful. So if you're just here for beautiful wedding photos, feel free to skip it. No hard feelings.
Still here? Cool. Let me tell you about FODSLR Macro Extension Tubes.
Macro extension tubes turn a regular lens into a macro lens. They are a lot cheaper than a dedicated lens, but also have some small technical trade-offs that I won't go into here. They come in "smart" and "dumb" versions, depending on whether they let your camera talk to the lens (to change your aperture and auto-focus) or not. These FODSLR (a brand name, apparently?) tubes are smart. (Dumb ones are a waste of time and better avoided.)
These are also remarkably cheap. I picked them up on sale for $25 - since the price has gone up and down, but I've never seen it above $40 (half the "list price" of $79.99). $80-$120 is a more common price for this sort of thing.
That said, there are some quality-consistency issues. My first set, two of the tubes would not come apart. A friend who bought these on my recommendation has also found his a bit "sticky". I returned mine (yay free shipping and free returns with Prime!), and the second set they sent are perfect. Take from that what you will.
I like them. A lot.
Of course, these tubes don't work in a vacuum - they're just one tool to add to your toolbox. The nice thing about extension tubes is they have no glass in them, so they are as good as the camera and lens you put them between. (The above photo also benefits from a professional speedlite, the DJ's up-lighting, and whoever lit about a hundred candles on the table.)
That said, these are straightforward to use. I'd recommend using lots of light so you can stop-down your aperture a lot.
Then just play around and have fun!