<p>This paper investigates the optimal subscription pricing strategy for software as a service (SaaS) vendors through a two-period game theoretical model that incorporates consumer heterogeneity in unfit cost. While existing studies have examined subscription, pay-per-use, and hybrid pricing strategies from various perspectives, our research classifies subscription pricing strategies into three empirically observed types: short-term, long-term, and hybrid, based on the duration of payment contracts. We analyze equilibrium market segments in both monopoly and duopoly markets and derive three key findings. First, in a monopoly market, a hybrid subscription pricing strategy universally outperforms single pricing strategies (short-term or long-term) in profit maximization. Under the hybrid pricing strategy, the SaaS vendor strategically raises its service prices while offering a larger price discount to its long-term subscribers when the proportion of satisfied consumers is moderate, the unfit cost is high, or the market discount rate is high. Second, while the hybrid pricing strategy maximizes profit, it sacrifices market coverage; the single pricing strategies achieve higher market coverage in a monopoly market. Specifically, the long-term pricing strategy prevails in low unfit cost environments, whereas the short-term pricing strategy emerges as optimal when the unfit cost is high. Third, in a duopoly competition market, the hybrid pricing strategy is not always optimal. When a SaaS vendor targets low-end market segments and faces rising unfit cost, the short-term pricing strategy becomes the optimal choice.</p>