I would reccomend purchasing an electric one that's suitable for both wet and dry use that way you can see what works best for you and it also means that they are easier to clean.
If you would like to continue using your disposable razor, a way to only use one at a time would be to purchase a trimmer which can get the hair to an appropriate length for achieving a clean shave.
Trimmers that come with multiple attachments are multi-purpose tools that can deal with unwanted hair in many areas. Here is a buying guide for trimmers
http://fotoepilators.com/trimmer/.