Do groceries cost more with Instacart?

No, groceries do not necessarily cost more with Instacart. But because Instacart is partnered with only certain stores, and the rest are merely listed as one of the possible grocery choices, if the Instacart personal shopper picks up groceries from a store that isn't an Instacart partner, then those prices will be higher due to a surcharge that's added to items ordered via Instacart. Instacart discloses whether prices are higher or the same as in store at the top of the app under the store name, once you click on a store.