Recettear takes place in a fantasy setting, and places the player in the role of Recette Lemongrass, the daughter of a shopkeeper who has left to be an adventurer but has mysteriously disappeared. As her father was in great debt to Terme Finance, she is forced by Terme's representative fairy, Tear, to continue her father's shop to repay the debt. Recette reopens the shop as Recettear, a portmanteau of hers and Tear's names, though also a pun on the word "racketeer". As such, Recette adopts the catchphrase "Capitalism, Ho!" as the player continues on with the story. The game's story is presented through text dialog and two-dimensional sprites, akin to a visual novel. There are some occasional spoken lines in Japanese, which remain untranslated in the English version.

The game is structured on daily cycle, with the goal to have repaid the debt of 820,000 pix (the game's currency) by the end of one month. Each day is structured into fixed periods. Time passes when the player operates the shop, goes adventuring for items, or returns to the shop after visiting other shops or guilds in the town, limiting the total number of activities that can be done in a day.

When the player chooses to operate the shop, they can place items on the shop's shelves, with certain spots, such as near the storefront window, being more lucrative to draw in buyers. When a potential buyer selects an item, the player can bargain to try to get as much profit from the sale as possible, but ineffectively bargaining will cause the buyer to leave without purchasing anything. Successful bargains earn points towards the player's merchant level, allowing for improvement of the shop and selling benefits once higher levels are gained. Customers may also bring goods to sell to Recette, requiring the player to try to barter and buy the item well below cost.

When adventuring, the player recruits a member of the local adventure guild. The player has access to only one adventurer at the start of the game, but as the game progresses, new guild members with various skills and abilities can be accessed. Through Tear's magic, Recette is invulnerable in the dungeon but cannot interact with the creatures within it, and instead watches over the adventurer, helping to collect items dropped by creatures or supplying healing items. The player has a limited amount of storage they can carry from the dungeon, and should the adventurer fall and cannot be healed, the player must drop most of their inventory to allow Recette to carry the adventurer out of the dungeon. Each dungeon features a number of randomly generated dungeon levels, along with a final treasure room at a specific depth. Items found in dungeons can be used as equipment for the adventurer, sold at the shop, or combined with other items to make more useful and valuable goods. The adventurer gains experience points and gains levels as he or she kills monsters, making the character more effective in deeper dungeons.

Should the player miss the debt payment deadline, Recette is forced to sell the shop and live in a cardboard box, the player can choose to restart the game retaining their merchant level and items, but not pix amount. Successfully completing the game unlocks three further game modes: "New Game+" which restarts the game but allows the player to keep their items and merchant and adventure levels from the completed game, "Endless Mode" where the player can continue the game indefinitely without having to pay any debt, and "Survival Mode", where the player must try to complete ever-increasing debt payments on a weekly basis. Survival Mode offers two versions, Normal Survival, where the items and levels are retained week to week, and Survival Hell, where these do not carry onward.