Grid Cubes?

[Sanderling]

I am looking around for some grid cubes for an extension to the guinea pig cage, and finally found these on Amazon: . It includes 20 grids. I just wanted to check that these look safe for guinea pigs, and whether I can get them cheaper somewhere else? I can't really afford to spend any more than this, it would be great if I can get them cheaper from somewhere else.
Or there are these: . Someone wrote in the customer reviews that they worked for their guinea pig cage, and they're cheaper than the wire ones.

Thanks in advance for any help!

 

[Sanderling]

oops, I seem to have added the same link twice! I meant to add this link in: http://www.amazon.co.uk/VonHaus-Interlocking-Shelves-Organise-Paperwork/dp/B00HUS1LYY/ref=pd_rhf_dp_p_img_2

 

[piggyfan]

The first grids look like they have 9 by 9 squares which are the same ones I have and are idea for a c and c cage.