Priority has some options, slightly out of the OP's $500 max, but they do have sales every now and then. The Priority Classic I bought, with fenders, rack, and front brake add-ons, didn't cost much more than that a few years back.
It got me back into cycling, but I ended up not riding it much after learning that the 3-speed upright tank style of bike (weight-wise it's under 30 lb, but handling is another story) wasn't that useful to get around non-flat Seattle. I realized that I much preferred to get to my destination as quickly as possible under my own power, because frankly there are hardly any bike routes connecting places people need to go (i.e., commutes and shopping) that are pleasant enough to enjoy at a leisurely pace.