For a cheep cover for indoors you can find them at Walmart. Costco sells a nice cover but it seems this is seasonal.
I got one for free off of craigslist. It's just a generic one that you can probably get at Wal-mart, but it fits perfect. The guy told me it was for a Toyota Tercel. It is really only good for keeping the dirt & dust off, but like I already said it is a perfect fit.