good but affordable drawing tablets?
Depends what affordable means to you, I suggest the wacom bamboo capture its 100 dollars and you should be able top work with it, it has sufficient specs and the only problem is that you may find it small.
You can always opt for an intuos small, its almost double the price but much better performance.
In general wacom release great products the issue is how much you're ready to invest. If you are going to be using this frequently I wold go for the intuos, if your only testing the water, Bamboo is good enough.
It is not the tools you have, its how you use them!