As JIP pointed out, $300 for a 28mm f/2.8 is far from a good deal, in fact it's a very bad one. $300 would be a decent but still not amazing deal for an f/1.8 in the same focal length, since that retails for under $400.
As for wanting a wide-angle... honestly, I would not consider a 28mm on a APS-C camera a real wide-angle by any stretch of the imagination. As you say it's similar to a 45mm lens on a 35mm film camera, which is really not very wide at all, being pretty much the "standard" focal length rather than either wide or telephoto.
For under $300 you could get the Canon 24mm f/2.8 instead... but even this would only be a very moderate wide-angle if used on the APS-C sensor. Personally if looking for a real wide angle then I would be looking for at least something around 18mm (as covered by a "kit lens" or standard zoom) or ideally something even wider.