Coaches do not buy everything on day one, and you should not have to. Start with one app. Add a line later. Go Complete when you are ready. Here is exactly how the codes work, so there are no surprises.
Every purchase gives you a new activation code. Codes are supersets, which is a fancy way of saying a bigger code contains everything a smaller one did, plus more. Nothing you already had gets taken away.
When you upgrade:
Buy an App Bundle with code CFR-UP19 to pay only the difference from a single app.
Move up to Complete with code CFR-UP30 and pay only the difference again.
Or go Lifetime, one time, and never think about it.
Each of those gives you a new code that unlocks more than your old one. You paste the new code into any app, and it simply replaces the old code. No migration, nothing to move, nothing lost. The newest code always wins, and it always grants the bigger set.
A one-year pass becomes Lifetime the same way. Buy Lifetime, paste the new code, and it never expires. You do not lose your remaining months and start over. You only ever pay the difference to step up.
So there is no wrong first purchase. Whatever you buy today keeps working, and whenever you want more, the next code stacks right on top of it.