Most venues offer a set of champagne flutes for you to use for your first toast and there are plenty
of Web sites

that offer engraved and personalized flutes you can purchase and, therefore,
keep for years to come. But there is also a store -- with a location in your home city, most likely -- where you can go and pick up classy and inexpensive toasting flutes.
Crate and Barrel is one of my favorite go-to places for kitchen must-haves, and my shelves are stocked with C&B barware (including my own toasting flutes) that I snatched up on sale or at incredibly great prices.
I bought red champagne flutes from Crate & Barrel for $2.95 a glass last summer, and my best friend borrowed them for her upcoming May nuptials. She has lovely flutes to use and she was able to check off "something borrowed" as well.
If you're not crazy about re-using the venues flutes or if you don't want to spend a crazy amount of money finding glasses that are perfect for you, try crateandbarrel.com or stop in your local store. And, just to be safe, buy one or two extra so if one is dropped or cracked, your champagne sipping won't suffer.