A menu of modules, one price each, on a Lite base. Pick a plan that bundles the ones you need, or build your own. Pay your first invoice by card and your workspace opens right away; add a module later from your plan, and it is on the moment it is paid.
What a company like yours usually starts with. Each is a set of modules at their listed prices; nothing is bundled at a discount that a plan does not already give.
Every module needs Lite. Prices are per month; pay for the year and you pay for ten months of twelve, two months free. Where a module has a usage allowance it is listed; more can be bought as a pack when you run out.