Most contracts in the UK do not provide any accommodation. Some agencies will provide local information regarding various deals on 'digs' other Connies have used. It really is worthwhile sorting out your accommodtion before arriving on site as you will not have a lot of time on your hands on your first working day.
If your lucky to get your first contract in Europe many jobs come with accommodation provided but the cost not always included in the contract. I have been on a number of European jobs and a few in Scandinavia. The standards are normally very high with at least a Bed & Breakfast deal included. In Scandinavia the digs tend to be located within the local town and may include a shared apartment, but again the standards are high. As its mostly a B&B deal or an apartment there are other budgeting facts to consider. FOOD! Many will opt for the 'Takeaway' path but after a few weeks of burgers and pizza its better to try out your skills with self catering (if the apartment has the facilities). If your in B&B a lot of places will not allow food to be taken in the rooms but if on a long stay many will provide an evening meal at a reasonable cost.
In the UK a few years ago it was not unusual to find camper vans and even tents located in the areas around the sites offering work. I have not used this option as I prefer a certain amount of 'Home Comforts' but I suppose if you enjoy the Gipsy life style then give it a try!