If you are looking to have a bouquet made up for any occasion when you need to consider what types of flowers you would like in it. You may not know many flower types but you can tell the florist what colours you like and allow them to recommend them to you. Ideally, you need to give them a budget to work towards so they know what you are looking to spend before they start coming up with ideas. If you know the names of certain flowers you would like to use then you could mention this to the florist or even show them pictures of bouquets you have seen which you like.
If the cost of the bouquet seems a little high then it may be because you have picked flowers that are not naturally in season at that time of year. If this is the case then these flowers will have to be grown in special conditions making them more expensive to buy. Choosing flowers that are in bloom that season will bring the cost of the bouquet down and allow you to get more value for your money. Searching on the internet can give you some great ideas of bouquets and if you are feeling brave you could try and make one yourself.