If you use 500 kWhr per month, that's 16 kWhr per day. A typical household installation for solar can provide 5-10 kWhr per day, at a cost in our area of around US $10,000-$15,000, installed. With the kind of usage you mentioned, you would need not a standard household installation, but a mega-solar power station, which would be hugely expensive, and difficult to place since you live in an apartment.
You would get much bigger return for your money by introducing a lot of energy efficiency measures into your household. Indeed, realistically, if you want to go solar, the very first thing you need to do is get your energy usage down the bare minimum. For a household with a full roof, it's best to get energy usage down to 5kWhr per day or less before you go solar. For small installations, like what you might be able to use with your apartment, you would want your energy usage down to 1-3 kWhr per day. Since you live in an apartment, that really shouldn't be impossible, but you'll need to start thinking hard about your energy choices. You don't have to lower your standard of living at all to use less electricity, but you do need to be mindful of the appliances you choose and how you use them.