If you want to tint it for full time and make sure there are no coatings on both lenses, then you can take your prescription glasses to your optician and they will tint for you. Before you have your glasses tinted, you can consult the price at first. I am not sure the price for tinting at your local place.
You can take them to any of the local optical store and ask them to tint the lenses of your glasses for you. The price of each stores differs, ranges from $30-60. But you can also do this in the online store, I've found Firmoo tint lenses for only $4.95. You mau check out at www.firmoo.com