You can go to any local optical store to have your eyes checked first so that you can know whether they are suitable for you and you can get your prescription. Then you can select Halloween contact lenses you like at your doctor's office or you can go to other optical stores to have a look and order them with your prescription. Or you can search them online. There are many online optical stores or websites which offer Halloween contact lenses with different colors and patterns. Here you can try lenssolutions.com to your find Halloween contact lenses.
The most convenient way to find Halloween contact lenses is to search it in Google. You can type the key words Halloween contact lenses in search box, then have a search. You can have many searching results, such as extremesfx.com. But you should remember that before buying contact lenses online, you should have an eye test and consult with your doctor. This can help you choose the most suitable Halloween contact lenses online.
Well,I think this kind of contacts can satisfy you with color and power. Meanwhile they are daily wear which makes them economical although they might be a little low-key. http://www.coastal.com/contact-lenses/splash-one-day-30-pack/prod96106.html
If you think want to be more outstanding, the link below might be your better choice. There are more kinds of Halloween contact lenses.