Contact your local authority who will have a list of local authority sites and private landlords. If you search the internet you will find local authority sites under their parks and leisure departments.
Sites are either owned by the local authority or from private landlords. Local authority sites are either classed as temporary sites or statutory sites. Statutory sites are protected by law.
Rents vary throughout the country but on average it is £60 for a yearly rental.
Submit your application as soon as you decide you want an allotment as most have waiting lists. The length of the list will depend where you are in the country.
You could be on your new allotment within week or months but in reality the average wait is 3 years. In some areas of London the waiting list is 15 years! So the sooner you put yourself on the list, the better.