My advice would be to buy LEGO tables for your kids!
The first step is to decide on the size of table you want. The next step is deciding what kind of table. These are some things you need to think about: materials, storage capacity, stability of the table (will it move around?), safety issues and durability. You may want to read this post on the best lego tables for kids.
I have used LEGO tables both at home and in preschools I have worked at, so I know they can provide hours of fun for a child while also developing their motor skills, and excitement while playing with LEGOs will last longer than just looking through them! And because children love moving stuff around I highly recommend getting a silicone mat from LEGO or Little Tikes along with a Magna Doodle board.