I think by "sketch pad thingy" you mean a Tablet.
Don't fuck around with $50 crap ones, you'll just be disappointed. There are a number of brands out there, but if you are looking to do anything approaching serious digital art there is only one for you: Wacom.
Wacom makes a lovely piece of hardware called the "Bamboo Fun". Yes, I know, it sounds like a kid's toy, but it is a serious piece of kit for the money. 6x8 drawing surface with a super-handy touch-sensitive scroll wheel and four buttons. I got mine for $110 over 18 months ago, it should be obtainable for under a Benjamin these days.
Personally, I use both a tablet and a scanner. (scanner: Canon CanoScan 5600F. LED-lit, internal power supply, oversized scanning surface) Don't go for the bells and whistles on either of these kinds of hardware. You can find really sweet bang-for-your-buck hardware around the $100 dollar mark. The two that I have are extremely high-quality products despite the relatively low price tag. Cared for properly they could easily give me a decade or more of reliable service.
The scanner/tablet combo is a more flexible and arguably quicker way of getting pages from concept to finished product. It allows you to get your idea out at first with a simple pencil and paper. When you're happy with the basic form of your work you scan that puppy in and go to stage two. Digital tablets, even quality ones, are hard to become natural with as far as drawing-from-scratch-on-a-blank-sheet goes. But they are wonderful
for digital inking and coloring.
This allows you to be quick and sloppy with your initial IRL pencil sketch. Things like scale, placement and overall final touches on your finished page can be dealt with digitally. You can even draw characters, foreground objects and background objects all separately on paper. Scan them in and layer them up using photoshop or GIMP. You can then tweak the size and placement of these individual 'paper' elements so that the finished scene looks juuuust right. You would spend ages doing foreshortening and scaling and other arty techniques to make background and foreground look 'right' together on a single sheet of paper. This is where digital touch-ups really shine.
Here's a super-crude example:
(NOTE: I am an aspiring webcomic writer, NOT an artist! I'm decent enough with a pencil to shape up story-boards, nothing more)
As you can see, this thing started as a peice-of-shit sketch on crappy lined paper. I belted out everything on this page inside of 25 minutes (and I really suck at drawing, if you have any art skill at all you could manage half that). Then I scanned that puppy in and went to work with my Wacom. Layered over the sketch is a digital ink and color job. If I gave a shit I could have then cleaned up the separate pencil layer to give it a cleaner look.
Here's what the starting-with-pencil-art scanner/Wacom combo can net you if you actually put in some effort:
(once again, I'm not an artist. I agonized over this fucker for weeks, you can replace skill with sheer time and effort)
If you look closely at Stogey here you'll note a digital ink and color job. Look closer at the shading and it doesn't look digital, because it isn't. All the shadows and shading on him come from the original pencil sketch. Shading with a real pencil on a real piece of paper where you are free to bump and smear and work it is, IMO, way
easier than trying to do it digitally.
I personally think choosing between a tablet or scanner is silly. Use BOTH! Each approach is well suited to a certain set of tasks, but when it comes to the business of setting up a comic page neither is strong enough on their own. You certainly don't have to work the combo like I do, but I think anyone with art skills can find advantage in using them both.
Digital inking is super-easy with Painter X
Color is a snap
Work goes straight to a digital format suitible for on-line publishing
Pencil work feels more natural, easier to get a concept started
IRL graphite shading kicks ass
Final product looks/feels softer and more organic
Combine the two and you have a recopy for success...