31Memorize is a free vocabulary building tool that utilizes the FSRS-5 spaced repetition system to enhance the learning process. Users can expect a cost-effective approach to vocabulary acquisition without the financial burden of premium features. Potential users are curious about how much control they will have over the vocabulary list they can create, suggesting a desire for customization in their learning experience. Spaced repetition is highlighted as a significant factor in effective language learning, which is increasingly relevant in educational technology.