They have 50's and I've even seen 100's, but those look like friggin tires.
I agree with the guy who talked about upgrading to an Oly bar. Even a walmart bar and try to find some used plates.
But, then again, weights are weights. Use the standard stuff until you get some loot for better stuff...you'll make a ton of progress anyway.
Hey, I started off with plastic coated cement plates, sand filled plates, and a wooden dowel.