That is correct. 

As mentioned on the Covert Commissions Bundle sales page:
The new members setup fee is waived.  You can find (optional) subscription services in your members area, rewarding you with your choice of ANY of our available and upcoming missions at reduced costs.  Memberships can be cancelled or even paused at any time - you'll keep access to EVERYTHING in your account (all missions, all leads etc will continue to make you money).  

So if you only purchased the Bundle, and have created your Covert Commissions account, you just need to activate your membership using the license code, enter it in the Dashboard area, and then you can access the Bundles and promote them without purchasing any of the optional membership levels. If you would like to activate more Missions, then you can either purchase individual credits, or upgrade your membership.