It's common and as others have stated it will depend on the property manager.

I know this is a nuanced topic and it is probably market dependent but I can't find any pictures of rentals' basements on listing sites.Any insight is welcome.

They're somewhat picky, kinda depends on which inspector you get and what mood they're in.

The ones I manage total to 20 bedrooms.These rooms rent for between $125 to $225 per week depending on room size and amenities in the room (beyond basic amenities may include: Desk, Tv, private entry, tenant controlled AC, additional storage).This month after padsplit takes their 14.25% cut of the revenue I am recieving, from the units I own, $15,230 from 3 homes.

You are talking somewhere around 5-6 points depending on how much you put down on the purchase.

It just depends on how much you pay to get that rate.

I've seen insurance premiums for flood go up to 5-6k on a regular single family home depending on the area. 

So depending on when you're looking to use the funds a fixed might make more sense. 

Quote from @Clarissa Finks:This all depends on what you need it for really..

@Natasha Rooney rates will also be different depending on if you have Credit or not.