I’m in optometry school and have worked in optometry offices for almost 5 years. First, if your glasses lens is scratched, there’s really nothing you can do to make the scratch go away or “repair” the lens–your only option would be to get the lens replaced. If you bring your glasses to an eye doctor’s office or Lenscrafters, etc, they can read the prescription of the lenses, but by law, are not allowed to make you new lenses without a valid prescription from an eye doctor. If you’re trying to avoid having an eye exam and really feel confident that your eyes are doing fine with your glasses (minus the scratch!), then you could bring your glasses in and ask the optician what the prescription is.
There are a few websites you can order glasses from, like chelseamorning pointed out above, that don’t check with doctor’s office on prescriptions, and you can just enter in the prescription you had read off of your current glasses. Our insurance covers vision, but my fiance wanted to use the benefits for contact lenses, so he has gotten ~$23 glasses from http://www.zennioptical.com with a sturdy frame and the antireflective (anti-glare and anti-scratch) coating on the lenses. Of course, you can get even cheaper glasses than that without special coatings.
You mentioned your contact lenses as well–for what it’s worth, the expiration date on contact lenses only refers to the solution that they’re stored in. Honestly, if you just disinfected the lenses overnight in multipurpose solution/hydrogen peroxide solution/whatever you use to clean your lenses, they would be fine to wear.
All that being said, if you had issues focusing in the past, it may be best for you to have an eye exam just to make sure your eye muscles are still doing okay, and you’re not harming your eyes by wearing an old prescription. You mentioned going to an ophthalmologist before–if you have medical insurance, you may be able to have an eye exam covered by that policy. Last summer, I worked in an ophthalmology office where patients with medical insurance would pay their medical copay, and pay an additional fee for the refraction (process that determines your glasses prescription) or a contact lens fitting exam (as several others have also mentioned). For glasses only, (and this was in Atlanta) the refraction fee was $39, and the contact lens fitting fees ranged from $50-125, depending on the complexity of your contact lenses and prescription.
If you don’t have medical insurance, or your copay is pretty high, you could also try calling a few offices in your area and asking what they charge. Most offices have a no-insurance rate that may be cheaper than you think, as they’re hurting from the economy as well, and want your business! Otherwise, as others have mentioned, there are usually specials you can find in the mall optometry offices, or at Target, WalMart, etc.
Hope this wasn’t too much info–I just got so excited seeing a vision related post! Let me know if there’s anything else I can help with, and good luck! 🙂