I mean they only sell base with a holding arm in the middle, removing the arm left you a circular plastic board...
Plastic board makes poor figure base, since figure base also serve as the handle for people to pick up the completed figure.
I do know MiniArt have that offer, and I had ordered a box. (currently out of stock, have to back order) But they are plastic and only got a single size.
Plastic bases might work well with cheap plastic kits; for white metal/resin kits, I would want a properly finished (polished, i.e. sand smooth, sealed with varnish and may be also stained) wooden base.