Effective and efficient skill-acquisition procedures must be identified to support individualized behavioral programming for children with autism spectrum disorder (ASD). To do this, practitioners and researchers may use assessment-based instruction. Prompts are a common teaching strategy to promote skill acquisition. The purpose of this applied study was to use assessment-based instruction to evaluate the efficacy and efficiency of within- and extra-stimulus prompts to teach conditional discriminations to two children with ASD. We identified stimulus prompts using a survey of popular children's games and conducted a tablet-based instruction readiness assessment. Stimulus prompts involved motion (within-stimulus) and pointing (extra-stimulus) to evoke correct responses in the presence of a discriminative stimulus. We used an adapted alternating treatments design with a no-treatment control condition to evaluate the effects of both prompt types across multiple sets of stimuli. Both stimulus prompt types were efficacious in facilitating skill acquisition for two of three participants. Little difference was observed in the time to mastery with either prompt. Neither stimulus prompt was efficacious for the third participant. Assessment results will be used to inform clinical programming to teach conditional discriminations to participants and contribute to research on designing and implementing assessments of skill-acquisition procedures.