If it's during office hours, they can pick up a spare key for no charge.

If you get a red card, you can not proceed.

If no other landlords in the area charge for heat, you'll probably have a tough time.

I see 3 days ago a charge for a whopping $390 was charged from BiggerPockets to my card.

In that case you will have to charge them in addition to the fees that are collected with Airbnb.

Maybe they’re charging over market or could find a buyer. 

Perform the same task in each app to ensure a fair comparison.Load a property with pictures and details.Market that property.See what your marketing looks like from the public's perspective.Submit a fake application to see how easy the process is.Run a credit/screening report on yourself.Enter a maintenance request, assign a vendor, and attach a fake invoice.Enter charges to the tenant's ledger.Enter recurring charges and automatic late fees.Sign documents electronically.Run owner reports.After testing a few apps, one should clearly stand out.

I made an offer on a double, it turns out that it's on two parcels with two separate tax cards but deeded together. 

They might charge you a couple hundred dollars, or they might not if they know they will get the work. 

Location of accountant: some accountants will charge more if they’re in a higher priced locationGeneralist vs specialist: if you want someone real estate specific, it will likely cost more.