Uh. You can't dual boot Tiger with anything on a Wintel machine. Gotta
be a Mac.

Having said that...I've heard of it running successfully on a
G3/350. Keep your eyes peeled on eBay. I just got an iBook G3/500,
384MB of RAM, 20GB hard drive, and wireless networking, for $385. But
then had to buy a charger (didn't notice in the auction it didn't have
one until after I won), and then had to buy Tiger itself, but again,
both got off Ebay for decent prices. All told, I spent just a titch
over $500, including shipping. And I even got a DVD/CDRW. You can
probably do better if you look hard, and certainly if you go for a
desktop model of some sort or another instead of a laptop. But they
tell me, get as much RAM as you can afford. At least a G3. And a DVD
drive is helpful so you don't have to trade in to Apple for CD's of
Tiger.