Apple can only charge what the market will bear. Since iPhone sales are trending downwards, a price increase is highly unlikely. For the time being Apple will attempt to charge the same amount for iPhones, but over the long term there will be a lot of pressure to reduce pricing.
Not only are economic conditions worsening, competitors selling higher tier smart phones. Ironically, the biggest competition for Apple is older iPhones. Since so many have iPhones that meet their needs, it reduces the chances of upgrades. I have an iPhone 6+ and I find it performs well and has outstanding battery life. I'm not going to upgrade unless Apple gives me a good reason to do so.
To sum up, no price increase, and a lot of downward pressure on iPhone pricing in the future. I certainly have no plans to invest in Apple stocks.