Hello!
I highly recommend the Wacom brand tablets, for the start you can go with a Bamboo version and if you're willing to spend a bit extra for a more professional one then an Intuous is great.
I personally use Intuos 5 (some years old) and it still serves me great. But before that I had a Bamboo that worked just as well

To be honest whatever you choose from Wacom all of them are awesome, no lag, doesn't scratch up easily etc.
Price of their tablets vary from 50eu and up as far as your wallet is fat.
P.S. I'd suggest small or medium size as any larger than that just takes too much space on the table and is a bit of an overkill (personal opinion)