There are a few different types of recruitment companies. Some specialise in finding people permanent job roles where as others specialise in finding temporary work on a regular basis. You may also find a recruitment agency that offers both.
You can decide which recruitment agency to use depending on what type of work you are looking for. If you are in desperate need of a job and do not mind what you are doing as long as you have an income the temporary work may be the answer but it is also worthwhile registering with ones that search for more permanent positions in the meantime.
Recruitment agencies fees also vary. Some agencies that recruit permanent members of staff charge the employer their fees whereas most temporary work agencies take a percentage of your salary to cover the costs. Make sure that you find out what and how their fees work before signing up with them.