Custom made Table Tennis Bats
A couple of the other answers here have mentioned the difference between a pre-made and custom-made bat. This is important to get your head around, but would like to suggest that it isn't as simple as it might seem.
For many years now I have been recommending the Palio table tennis bats to all my beginners. These come pre-made - meaning they don't have to worry about choosing rubbers and blades from the thousands of different options - but are made using custom-made quality rubbers which are then glued together like a custom bat.
Basically, most pre-made bats will have the rubber/sponge permanently fixed to the wooden blade. The Palio bats have the rubbers glued down with table tennis glue so that they can be removed and replaced. The rubbers used - often CJ8000 - are also custom rubbers than can be bought individually. Most premade bats use cheap rubbers that aren't available individually.
The Palio pre-made bats are the best of both worlds and the latest Palio Expert 2 bat is very good value too (£29.99 or $39.99).