Services
Adventurers don't only require equipment, weapons and armour, often they will need to to pay for passage or room and board. Sometimes they may even need to hire professionals to assist them. Maybe the wizard in your party is a lawyer, but if not, you'd be foolish to invest all your hard won treasure in buying that keep on the borderlands without hiring someone who can read the contracts and make sure the deeds are in order.
Travel and Transport
The world is a big place, and even just seeing a tiny fraction of it is an adventure on its own. Travel and transport can be extremely expensive, but sometimes the most efficient way to get where you're going is simply to pay for passage.
News and Messaging
Information is critical to adventuring. If there is trouble in the area - such as a hill giant menacing nearby farms, the kidnapping of a local noble, or the theft of a holy relic from the local cathedral - this information will be distributed in the news sheets and called out by criers in the town squares. In addition to publicly available information, messaging services allow party members to keep allies and each other updated during investigations.
Entertainment
In a pre-industrial society, the majority of entertainment is performed publicly on street corners or in public squares, with performers passing a hat among the gathered crowd. During street fairs or festivals, vendors and merchants will hire performers and pay them up front to attract more customers and keep them around longer. In towns and larger cities, theatres, sporting fields and arenas, a even grand performance halls and stadiums will attract premiere talent including travelling theatre troupes, musical ensembles and sporting champions, drawing large crowds and charging admission to the venue.
Meals and Menus
Travel rations and the basic board provided with lodgings may be enough to nourish the body, but socializing around the table is sometimes necessary to feed the soul. Additionally, overheard conversations in inns and taverns are often the key to adventure. In the long run an expensive meal is not only more satisfying and more fun, it can also pay for itself. Note that in pre-industrial societies, prices for food can vary enormously, and food must always be local and in season; fresh fish will not be found far from the coast or a river, and fresh fruits and vegetables will not be available in winter. Prices for menu items below are for standard inn or tavern fare. Specialized restaurants, or establishments centered around fine dining will charge two to twenty times these prices depending on quality and reputation.