This is actually an old project that you may have missed because it was posted together with some other projects as a set. Since people are looking for garden ideas I thought I would post it as a standalone. Who knows, it may give you some fresh inspiration.
I (still) have a couple of very large concrete planters in my garden. I used one for my BBQ Storage Bin project.https://www.hometalk.com/44268116/outdoor-bbq-storage-bin
For this table I emptied out 2 and painted them with white PVA house paint. A tip on finding cheap planters: many corporates rent their plants from plant rental and maintenance companies. The plants are replaced every so often and the pots and planters are then sold to the public for next to nothing. Phone the rental companies in your area and find out what they do with their old pots.