I'm going to give some free advertising to a company I've bought a BUNCH of cast resin bases from through e-bay recently.
Rusty Nickel Miniatures
Their home page:
http://www.rustynickelminiatures.com/
And Facebook:
https://www.facebook.com/rnminiatures/
I havve ordered over 50 bases from this company and they have all been exceedingly excellent quality. I personally am going with their Urban Battleground set, and have sets of mostly 32mm, but have also purchased 10 of their 25mm set for my scouts, as well as one 60mm base for my eventual Librarian Dreadnought.
The price is also quite reasonable for packs of 10x 32mm bases; just $6.50 before shipping.
Here are a few of my recently completed minis on these bases for example's sake:
They paint up fantastic an look great with urban greyscale shades as I've painted them up here.
Highly recommended here. Just offering that as an alternative to
MDF or Acrylic bases. Hope it's helpful.
Take it easy.
-Red__Thirst-