When ordering printed materials one of the decisions you will be asked to make is the weight of the paper. This is always referred to as the GSM. This is the Grammes per Square Metre and is basically the weight of a square metre of a single sheet of the paper in question. So if a paper is referred to as 135 GSM you know that a square metre of a single sheet weighs 135grammes.
The main consideration when selecting the paper, or stock as most printers will refer to it, is the appearance of the finished leaflet. A higher GSM can give the impression of a higher quality item which will reflect on your business image. That leads us to another important consideration, cost. A higher GSM usually costs more but that cost is often not too much of a difference. You have to remember that the cost of the paper is only one part of the whole package but can dramatically affect the appearance of the finished leaflet for a small amount extra.
Another major consideration is in how your leaflet is going to be distributed. If you are going to post the leaflet, then you have to consider the postage cost, having a leaflet that is too heavy might take it into the next weight bracket and cost more to send. But then again a heavier GSM, say 230 GSM upwards, could possibly be sent as a postcard and therefore save the cost of an envelope and someone having to take the time to insert it into the envelope. If the leaflets are to be distributed by hand then a lower GSM might suffice as they are going to be carried and a lower GSM means that more can be carried at once.
Ask your printer to show you samples and take advice from them. Use a well established leaflet printing company such as Circle Services and you can be assured that they have built their services on years of experience and will be offering the best value for money based on that experience.