The "SaaS valley of death" is that zone where a product is priced too cheaply to justify a sales team (e.g., <$25k/year) but too expensive for credit cards (e.g., $5k/year). So presumably the upper range is around $400 a month?
But that sounds theoretical and I'm curious to hear from those who have had real, trial-by-error experience playing in this upper SaaS pricing range.
You will be surprised about upper limits on credit cards. But it is more US centric as our european clients prefer bank transfer for larger amounts.