One of the simplest hen party themes which actually does not require lots of additional expenses is construction workers. This them can be quite meaningful as bride-to-be is actually building a new life. Let the ladies help her constructing her the last day of freedom.
the theme requires the special jacket which is usually used in every car as a security jacket in case of repairing a car in a dark. This yellow or pink jacket can be used in a hen party. Just find some jeans, make them little dirty, put on the jacket and a helmet with security glasses and you are ready to go. Also you can make some construction worker make up – just a couple of lines of dirt on your face. Also you can wear white working gloves in order to hide your amazing manicure as it does not fit to general dirty image.
The venues can also be related to construction. For example you can ask to fix a car engine, mix a bucket of concrete, clean the sink tubes etc. These works are usually done by men, but every married woman should learn how to do this in case her husband gets drunk or finds any reason to stay longer at work.
These venues will cost you a few extra pounds, but generally it will be quite cheap, but fun. After the venues, bride-to-be should read the oath mentioning how she will construct her family life and not forget all the participants. The hen party can be finished in some loud bar with real workers. Of course you will get some attention as usually ladies do not wear such clothes and do not walk in dirty faces.
Just be creative and you can definitely organize a cheap but meaningful hen party.