I took my cavern class with Robert Neto
Chipola Divers - Home and my class was far less than 1K. If there is only one student then the class is $400.00, but if there is two or more students in the class than it is only $300.00. You will be diving at the Mill Pond and you will get your fills at Cave Adventurers. He charges by the cubic foot of gas for fills. This means when your tank if half empty he will only charge you for the gas it takes to fill you back up. Robert can direct you to plenty of cheap hotels to stay in for the two day class. You don't have to go out and buy a sidemount rig or doubles set-up. It is not required at the cavern level. I have seen several people taking cavern in total open water gear. Robert even has reels for you to try out during the class so that you can use several different types so that you can try it out so that you can make an informed purchase later on. Robert's email and phone numbers are listed on his site.