Although I agree with cajon about small hotels having more character than chains and I am sure you will be happy at the Adventure Inn, I am not sure where you are reading that the Holiday Inn Express SJO charges $22 to get you to the airport. (Are you sure you are not looking at one in San Jose California?? or else perhaps the price to take you to Pavas the other airport which is about 20 minutes away)
I have taken that free shuttle to and from SJO many times from the airport without even staying at the Hotel.
Also if you look at their website they clearly states
"You'll love the free 24-hour airport shuttle, wireless Internet access, daily breakfast ........ "