A/B/n testing tools & softwares are prevalent in the market. Their operating principles are the same for multivariate testing tools (see more details on operating principles on the previous link).
An example of A/B test deployment process:
A/B/n tests are simpler and consume less resources than MVT and therefore are cheaper.
Some professionnal self-services are affordable for a few dozen dollars per month and offer free trial.
Furthermore A/B/n test functions are sometimes embedded in web analytics solutions, CMS or ESP platforms.