Tapas are not starters. If you decide to have tapas it will be either a quick snack or you will have several and make a meal of it.
A 'Tapa' is a lid or cover that originated many years ago. A slice of ham or cheese was served with your drink and was placed over the top of your glass. The tapa is an integral part of Spanish culture. Most Spaniards will take tapas with a drink.
A tapa is normally a quater sized version of a full meal and the content will vary from region to region. For example on the coast you will find seafood tapas in abundance. Inland you might find that meat is more on the menu such as veal or venison, beef or pork. Each region will also have its specialities.
Gone are the days when most bars gave tapas for free, altough a few still do. Nowadays there are speciality tapas bars that serve nothing else.
There is a popular chain of bars that serve tapas 24 hours a day. You simply help yourself from the bar. Each tapa comes with a cocktail stick. The number of sticks on your plate at the end of the session will be counted and charged accordingly. Dishonesty is very rare in these bars and few people actually eat the cocktail sticks to avoid payment.