Need Transformer Information

We have a small "haunted" house for which my wife bought a number of
lights (pumpkins, etc.). Unfortunately, they're all the battery operated
3v type (I'd have preferred 12v ones), and I'm going to "transformerize"
them.

Appropriate transformers seem to be rare in my immediate area, with the
ones I see at Radio Shack being relatively low in amperage capability,
less than 1000 ma. There are lots of the lights I need to connect to one
or two transformers if possible, so I'd guess at least 2000 ma or so.
There are a few electronic supply stores a bit further out from my home,
and some online sites I can go to.

That leads so my question - rather than buy DC transformers, I'd rather
use AC, less complicated internally, and, hopefully cheaper. I'm
wondering whether the lights will "notice" they're being fed AC rather
than DC. Anyone comment?