The median AI SDR contract runs about $45,000 a year, signed annually. The failure mode is not that the software breaks. It is that the list was wrong, you find out in month three, and nine months of payments remain.
Everything here caps that exposure at a month or a quarter. AiSDR is the notable one: the only full-stack agent in its tier that publishes a number and bills quarterly, so you can discover the motion does not work for about $2,700 rather than $45,000.
Worth knowing before you shortlist on this basis alone. A vendor selling only annually is not necessarily gouging you, and annual pricing is often genuinely cheaper per month. The question is whether you have enough evidence yet to make that trade.