I have a painting that was left to me. I'm pretty sure it's an original, I live in an small town so there are no galleries I can go to for help. All the sites I'm looking on cost. I want to know how you can tell if the painting is authentic and how would I get it appraised.

A work of art is worth what someone will pay for it. So you have to look for comparables. From labels on the frame, on the back, or a signature on the painting, can you identify the artist? If so, do an internet search on 'name artist' and see what comes back. Keep an eye out for free apraisal events like Antiques Roadshow and the copies that local places run. If you are convinced that the painting is probably an original and may have value, then call an art museum or art department that you are willing to travel to and ask whether you can show someone the work simply to make sure it is not a print. They may be willing to go further.
But much beyond that is going to cost some money.