Mecenary buying quickie

Quick question...

If i was to buy a 3 slot Mecenary, can i later then buy another 3 slot?

Then then what happens if i want to buy the final 2 slots later? that mean i got to buy 2 single slots?

To be honest i want all 8 slots but the £30 is alot for me at the moment as ive just had a baby and currently off work and only earning basic salary.

i guess so. tbh if your short of cash i wouldnt bother with it, its not needed

I'd say hold off on buying the merc slots.
If you really do want them, and the total 8 are your goal, wait until you can buy all 8 in one package.