Where can i buy toy story merchandise at fan conventions?

None of the supplied evidence mentions specific vendors, conventions, or locations where Toy Story merchandise is sold. The only verified fact is that Toy Story is a known entity. Because no details about convention stalls, official stores, or event listings were provided, we cannot state a definitive answer. If you are looking to purchase Toy Story items, you might consider checking official Disney merchandise vendors or the Disney Store, but confirmation would require additional, reliable sources.