I'm going to give historical prices. For D&D prices, multiply everything by 10 or so.
The middle ages are an extremely 'coin poor' time. There isn't enough coinage to really represent all the wealth that is out there. As a result, the value of coin is highly inflated. Besides which, producing coinage is expensive, so the value of coin had to be high.
An inn or tavern probably wouldn't have a menu as such. For one thing, menu's are on paper - which is expensive.
Upon agreeing to stay in an inn, you would be provided with fare appropriate to your station, for which you'd pay some lump sum which would include the price of your room. If you wanted a special request, the tavenkeep would send some boy out to procure it, and then cook it when it arrived.
Most houses could become makeshift inns in a pinch, especially if the traveller was poor. In fact, inns were basically big houses. You would likely eat with the family in a common room, and sleep in that same room when the family retired for the evening. Richer people would dine privately, often in rooms that family members had been kicked out of to make room. Because they were basically houses, an innkeep could and probably would turn down anyone that looked ill-favored or which did not come with a good word from someone that the innkeep knew. Sellswords (what we would call adventurers) in particular would be regarded as people of ill-repute and would be unlikely to get rooms or at the least would have to pay extra.
A days wage for a common laborer was a silver piece in antiquity. By the time you get to the late middle ages, inflation had forced this up to about 3 silver peices per day. Of course, you wouldn't likely get paid in coin - coin poor society remember. Instead, you lived in a barter economy. Still, travellers had to have coin, which also meant that they were rich and so the prices in an inn would probably be inflated.
To those of a jocular inclination, ale would be sold by the cup. You would have to provide your own cup, and so most everyone wore a cup. A cup of ale would run you around two coppers, or if you were local you could run up a tab and then pay off the innkeep in goods - say a piglet for when the innkeep needed to feed a travelling noblemen. A full meal and room for the night might run a wealthy merchant 5 silver peices. A poorer person would room in someone's stable and eat bread and a cup of weak watered wine for a few coppers, or a half days labor.
A typical meal in the middle ages was mostly bread. Bread was toasted in the morning because it would be getting a bit dry and crusty by then. Bread is not very filling, so most people would eat a loaf - preferably with a bit of butter, oil, or honey if they could get it. To thicken them up, medieval breads consumed by the moderately wealthy are often baked with things in them - olives, fruits, nuts, pickles, cheese, garlic, or even meats - usually pork because pigs may forage for thier own fodder in the forests. Wealthy people would eat pies, which is basically a stuffed bread with more stuffing than bread.
Loaf of Bread: 1-3 cp
Stuffed Bread: 2 cp - 1 sp
Pie: 5 cp - 2 sp
Another common staple was porridge. Porridge is basically a soup of whatever grains you have at hand. Oats would be typical because oats can be grown in poor soil. Milk, butter, salt, and honey is added if you have it. Gruel is the low end of medieval fare - more water than meal. Going up we'd get things more recognizable as soup - typically lentils with whatever vegetables could be stored in the cellar (turnips, carrots, beets, onions, garlic, etc.) Since utensils are valuable, and clean water scarce (especially in the winter), soups were often poured over bread or into bread bowls to avoid soiling anything. Going up from this we have stews, hearty things filled with all sorts of delicacies like meat.
Porridge: 1-3 cp
Soup: 2-5 cp
Stew: 5 cp - 2 sp
Meat was expensive. The most common meats would have been dove, pork, lamb, and goat. Mutton, beef, cod, duck, chicken, rabbit, herring, oysters and grouse would have been a step up - rare meals in tradesmens households. Goose, swan, peacock and such a step up from that, and venison the most expensive meat of all. Because meat does not keep well once slaughtered, its available pretty much in two forms - salted and whole roasted. Naturally, beef in particular is almost always only available dried.
A bit of salted meat on sundays to flavor his soup might be as much as a peasant can afford. On feast days, he might purchase as large a fowl as he could afford and roast it whole - a custom which continues to this day although being rich we don't eat so much dove any more.
Salted meat: 3 cp - 1 sp
Roasted Dove: 5 cp
Roasted Duck: 3 sp
Roasted




: 4 sp
Roasted Piglet: 5 sp
Roasted Lamb: 6 sp
Roasted Kid: 6 sp
Roasted Goose: 9 sp
Roasted Peacock: 1 gp
Roasted Swan: 2 gp
Roasted Boar: 3 gp
Roasted Ox: 12 gp
A merchants meal would be served with wine, pickles, cheese, and a bit of fruit when available. This would add an additional 1-4 cp to the price of a meal.
Wealthy people would buy much much more than they could eat and sample a bit of each dish. This was because the right to eat your lord's leftovers was considered a significant part of the lord's retainers salary. Think of it as a medieval benifits package. Thus, a noblemen might purchase a meal worth 50 gp (a year's wages for a peasant).