It depends on if you actually wear glasses, or just want them with clear lenses, and how much you are willing to spend. As I wear glasses myself, I have bought several Ten inspired spectacles over the years and I have found that at the opticians, Ten style specs are usually at the low end of the price range.
Still not the cheapest, but the best way to go.
One thing you can best avoid though is going for black spectacles. The ones used on the show (there were different models) were always brown. Black ones are going to look far too dark.
The other thing you should avoid is wearing glasses with a prescription other than your own. At best these will give you quite a headache.
If you just want clear lensed ones, you can usually find them at your local jokeshop, but these do usually tend to be black though.