You'd do good to care about the numbers a bit more yourself. The blue pot from the store gives 30 extra natural mana regen.
That means 30 extra mana every 4 seconds or 7.5 extra mana every second (about 10% of a mana potion).
Yes, you are right. That will be the solution for all your mana issues... But keep buying them. Funcom can use the money.