I don't have a lot of experience with going to an eye doctor and receiving a prescription. I personally have an astigmatism, so I cannot wear certain types of contacts. This usually speaks in general for contact lenses, so please keep that in mind. Although, I hope to add more when I finally get to try out sclera lenses.
STORAGE:
Always clean your lens solution after wearing and at least once a week if you are not daily wearing. This cleans out old bacteria and keeps your eyes clean. Throw out your lenses and the case after the expiration date (1 month, 6 month, year, etc). And especially if the lens gets torn or dried out. Rarely, can you remoisturize the lens after it has dried out, but it has been done before. I have used it for my brown lenses, but I wouldn't risk doing it more than once.
SITES:
My favorite sites used to be pinkyparadise.com and honeycolor.com, but since the US required current eye prescriptions, I have been unable to order from them. They have amazing deals as long as you are able to maintain your yearly eye exam. The current one I use is Uniqso.com, who sells wigs as well. I use them more often than not now because they have just as expansive a selection as the other two and has a bunch of amazing deals. I also love that they have sclera lenses as well.
I would suggest for easy storage, if you have more than two pairs of contacts, to write down the color or main use for the contacts. So, for my Uranus lenses, I have "Uranus" written on the top of the right lens cap. This also helps if you have different color cases, which the sites listed above usually send a case per pair of lenses you buy. Otherwise, you can buy a load of cases from Walmart or Target for relatively cheap.
Again, this is just my experience, and I can't tell you about glass contacts, or scleras. I only have plano lenses and cannot wear certain lenses due to my astigmatism. If you have any questions, please let me know!