Keep in mind that several stations that are Religious/Christian are that in format alone. Salem would tell you they are a for profit company and as long as religion pays the bills (or talk or business talk or anything else), they'll stick with it. Those from 88 to 92 FM are typically the ministry owned stations although they might own commercial frequencies and AM stations too. Lots of the AM religious stations really struggle.
The model in Christian Radio was you had hundreds of ministries that paid for airtime. One by one they changed to a model of: we no longer pay you but you can run us for free and we'll give you a piece of each donation that comes in each month from your listening area. That left local ministries.
Local ministries, if you can find interest without the congregation taking a year to decide to go with it, it is typically the person doing the program that pays from their wallet. They can never afford much...usually 15 to 30 minutes a week.
Advertisers on the religious station, assuming you are on a commercial frequency: the station will have the struggle of gaining enough listening audience within the primary trade area of the advertising business to actually produce any advertising results for the business. Generally you are stuck with mom and pop businesses with very small budgets who might stay on as long as their minister at their church stays on your station.
It doesn't matter if you're in a metro or not, it's what the willing buyer can afford and sometimes you hate selling 'that' client but when it means the difference between meeting payroll or paying the light bill, you do it because selling religious radio is more about who calls than who you call on. A caller is ready to buy but one called on likely never thought about buying.
So, yes, lots of religious stations sell not only program time but they sell commercials. The problem is there's never enough program buyers nor business advertisers and neither seem capable of paying anything close to what you thought that amount of time might be worth. I've sold for as little as $20 for a quarter hour and lots of $3 spots (10 seconds) to businesses just to keep things rolling. Then a Spanish language broadcaster bought a few hours and he became a success. In a few years we had 8 times the revenue by leasing hours to foreign language broadcasters. Our job was to take their money. They did all the work: programming, sales, promotion. We gave them a radio signal at a rate per hour.
