Pricing keeps coming up, so we're going to look at what we can do. We don't want to get into providing accurate prices (they change too frequently and it'd be a game of cat and mouse; and the intention is not to be a price comparison site) but it's been asked for enough that clearly we need a way to at least show the difference between a $50 toy and a $3000 rig.
I'm curious about the negated filters - why would you want to only consider things that don't have a feature? If you don't care about a feature, you can ignore the filter for it, but why (for example) would you specifically want something that doesn't have GPS or doesn't have Altitude Hold?