Price per share is set at each priced round by dividing the valuation by the total share count, and it's the unit that makes ownership concrete: if the PPS is $2.00 and you invest $50,000, you own 25,000 shares. Every subsequent round establishes a new PPS, and comparing it to the price you paid is the cleanest way to see whether your position has marked up or down — a later round at $6.00 against your $2.00 entry is a 3x paper gain on price alone.
Your effective price per share can be lower than the round price when you came in through a SAFE or convertible note. A 20% discount means you convert as if you paid 80% of the round's PPS, and a valuation cap can push your effective price lower still. That gap is the reward for taking early risk: when your SAFE finally converts, you may end up holding more shares per dollar than the investors who priced the round. Effective PPS, not the headline round price, is what determines how many shares you actually own.