Api learning, testing, listing fee 2018

newbie here, several posts say trade leader needs to pay a listing fee to test the api. those are old posts from 2010 etc, so i’m wondering if this is still the rule, or is there a sandbox that can be used for testing within a 30 day trial period window?

how much is the listing fee? is it $99 per month, or $99 1 time charge?

when I tested the API more than a year ago, there was an option to designate a system as test system. I ran all my technical tests on such test system.

Not sure if it still exists. else the option is to create a free system that will remain free for 2 weeks and do the tests in this window. if not enough create another free system and repeat.

Listing fee is $99 / month of course for live systems.

thank you for your reply. there is a webinar on wednesday so i plan to attend that and ask more in depth questions.