Show me the money
For wedding photography your main initial cost will be the kit. You’ll need a range of lenses from wide to telephoto, and ideally two Nikon camera bodies. To minimize the cost you could consider hiring the spare body and extra lenses, but make sure that you are completely familiar with them before the event.
Travel, advertising and replacing or buying new kit won’t be cheap if you want to do more than a few local weddings or commissions per year.
How much can you earn?
You should be able to make around £50 to £100 or more from a typical portrait session, depending on the time involved. For weddings you should look at making £500 profit at the very least for a full wedding shoot, as this will take at least three days of time preparing, shooting and editing the photographs.