SLR or Point and Shoot? That would be my first question.
Next, is what kind of results is she looking for? Stuff for memories, or stuff for publication? Wide Angle? Macro?
When I first got into underwater photography I started with a simple setup of an Olympus C5050 and just the housing. No strobe.
It worked very well for macro, but any wide angle shots would be very blue. And if you leave the flash on taking a wide shot, it will blow out any backscatter in the water.
Once I added the single strobe above, I was able to do a lot more.
Here are some shots with that above rig
There are many advantages to this type of rig.
Very Portable
You can go from shooting Wide Angle to Macro on the same dive
Affordable
This biggest disadvantage is shutter lag, and lots of it.
This was my main reason for upgrading to a SLR rig.
I started with just 1 strobe, a housing, and one port for shooting the 18-70. Not a bad combo, but I soon started finding shots I couldn't get. I wanted more wide angle. Better macro. I need some focus assist. I wanted to fill in shadows....
I ended up with this monster.
It's an addiction that is hard to curb. This rig was relatively tame underwater, but traveling with it was very very hard. Managing lens swaps and port swaps above water a pain. If you aren't on a photo friendly boat, you'll find divers that toss their masks in the rinse bucket, or just in general are rough with your gear.
While I did get some very satisfying shots. I don't find them to be that much, if any better than the ones I got with my point and shoot. Not to mention the greater expense and inconvenience I was putting myself through. I started consuming every moment of my diving with photography. Both in the water, and during my SIT, swapping batteries, lenses, ports, memory cards, etc...
And for someone that goes on maybe 2 dive trips a year, I finally put a stop to it.
Here are some shots with the D70 rig.
Eventually I dropped photography and went with Videography. I had a video camera in a very compact housing. No lights. And it had a monitor integrated into the back. Easy to travel with, and almost as small as my point and shoot camera rig. Just dive and point, and then you do all the editing when you get home.
Here is a video I shot.
Anyways. Sorry for the long history and rant. Just some things to think about it.
If she is looking to stay under $1k, I'd say look at
Ikelite.