Where do you buy welded steel grating?
 

Like they use for drain covers? I don't want to pay to have it shipped.

Call your local municipality they can tell you who they get their covers. Odds are their suppliers are local.

That could be a dozen differant things your talking about, got a picture or web site?
If it's something like expanded metal I'd be contacting some local steel supplyers.
Should be under steel in the phone book.

Any local welding dhop can make one up, if it is a odd size, our you are wantinting to use rebar.

They would need a drawing with specific dimension.

If you want chase grating, you'll need a local metal supplier....... who will add shipping to his price. There are lots of different sizes, depending on what load it needs to bear. Thickness of the bar x depth x spacing

In my area a concrete supply place makes those up--they have window wells---window bucks--and grates of all sizes---and a fabricator---

See if you have an old fashioned yellow page book and look for 'building materials/concrete supplies