It was great!
They had two big laundry hampers (maybe they were fancy butterfly transportation devices?) full of butterflies.
The gift shop at the Texas Discovery Garden is AWESOME for butterfly and bug stuff. We didn't get anything there, because the kids were melting down and my husband was just melting. But it had every possible butterfly-related item you could think of, including a zillion different sticker books for $1.50. You can pop in the gift shop without paying admission, if you need to stock up or something.
We recommend the garden, though, and will probably come back another time! In the winter, that is.