Yes, you can develop and deploy an app built with any ArcGIS Runtime SDK for free. You will need to have a Developer Account (also free) and get your Lite license string from the License page.
Note that if your app's needs Runtime capabilities that are not available at Lite level, then you will need to purchase appropriate Base or Standard licenses (Advanced level is not relevant to the iOS SDK).
And of course there may be costs for using Location Services over the free monthly allowances.
