If you can get a decent tablet for $100 then go for it :p
I lucked out and found a brand new LCD tablet on ebay, and scored it for $550 USD. You can probably expect to pay at least $1700 for a new one of about the same size (15") if you buy directly from the manufacturer, but I see them pop up on auction and clearance sites all the time for way less. Hell, you might even find one refurbished. In my case, the manufacturer decided to get out of the tablet business and liquidated its entire stock at clearance prices. A smart fella decided to buy a bunch up and ebay them with a small markup; when I received mine it was in the OEM packaging in mint condition. For the record, it's an Optoma PI500 and it's pretty badass (the specs are identical to the 15" Cintiq, and in some cases better), should anyone find another one I highly recommend it :p even though the product has been discontinued the manufacturer is still honoring the warranty.
Another thing to consider is that most LCD tablets DO have some shortcomings as far as reduced pressure sensitivity; mine only has 512 pressure levels as opposed to the 'standard' 1024, although honestly I can't tell the difference. LCD tablets can also be less responsive (meaning the pen refresh rate is lower and thus extremely fast movements won't be tracked as accurately), although mine is pretty damn smooth, and most high-end painting software will interpolate splines between brushstrokes to compensate anyway. I think Wacom's latest Cintiq model eliminates those shortcomings, in any case.
If you have the extra money and the sensitivity tradeoffs are worth being able to draw directly on the screen, then an LCD tablet might be worth the extra expense for you. It was for me, anyway.
