When you see some advertisement featuring the prices of any particular thing, you need to understand that the mentioned price might not be the actual purchase price of the commodity. In order to provide the sales pitch for their products, the companies tend to provide those rates which are some basic rates and the additional price component has not been added to it even while the actual price shall comprise these as well. The same is true for the cheap air tickets as well. There might be a big difference between what is being projected in the marketing material such as the leaflets, newspaper ads and on the internet and what will actually be charged.
It happens quite often that on seeing the cheap air tickets, you initiate the process of online flight booking but when you reach the fag end of the whole process, you realise that there are terms like the processing fees, service charges and a number of taxes which have been added to the price and will be charged from you.
That is the precise difference between the two terms. The moment you see some sort of asterix or other sign on the superscript of some price mentioned on the marketing materials, you can understand that this price would come with certain limitations or that there is some more component which needs to be added to the advertised prices. The marketers say that the prices that are mentioned are meant only for attracting the customers to them and are not meant to be the actual prices. But, other people often argue that this is not the right practice since these are misleading in nature. The true prices shall be mentioned at the outset and even the additional components of prices shall also be mentioned.