According to the provided sources, there is no information on whether there is a limit on Advil purchases. However, it is important to note that the FDA has legal requirements for the sale and purchase of drug products containing pseudoephedrine, ephedrine, and phenylpropanolamine [2]. Additionally, there has been a shortage of children's Tylenol and Advil, and some retailers have limited the amount of these products that customers can purchase [3]. It is possible that individual retailers may have their own policies on purchasing limits for Advil or other over-the-counter medications. Therefore, it is recommended to check with the specific retailer or pharmacy for their policies on Advil purchases.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ADVIL
[2] https://www.fda.gov/drugs/information-drug-class/legal-requirements-sale-and-purchase-drug-products-containing-pseudoephedrine-ephedrine-and
[3] https://www.usatoday.com/story/news/health/2022/12/19/shortage-kids-tylenol-advil-purchases-limited/10927952002/