Ebay is a great place to find an acoustic guitar, especially if you are a beginner and want a quality instrument for less than you would pay in stores.   I have played guitar for more than 30 years and have purchased several nice guitars on Ebay.  So can you!
        Acoustic guitars come in two basic varieties:  classical (which uses nylon strings) and steel-string.  Classical guitars are primarily used for classical music, Latin music, and some jazz.   Steel-string guitars are used for folk, pop and blues.   Steel string  guitars are best for accompanying singing, or playing within a folk group or bluegrass band.   And yet, Willie Nelson plays a classical guitar! 
        If you do a search on "Acoustic guitar" you will get more than 10,000 hits, and a lot of cheap guitars will turn up.    Steer clear of a cheap guitar; it won't last and will not play well for you.  Do a search on a guitar Brand, such as Yamaha, Washburn, Seagull, Alvarez, Takamine.   Or, using the Advance Search function, you can narrow the price range from $100 to $200.   You should find a good beginner's guitar for around $150.   Be sure the guitar is new, not used!    Insured Shipping within the U.S. will cost around $30.00.   If a hard case is included, then it will cost around $40.00 to ship.
       Before buying the guitar, Ask the Seller if the guitar has been "set up."   This means that the instrument has been adjusted so the guitar plays easily.   Many Sellers of inexpensive guitars do not do this.  However, every new guitar should be "set up" - even if you have a local guitar craftsman do it.   This costs around $50.00 and is well worth it.
       Last, get some good strings (Martin SP, D'Addario, or DR  Light Gauge are very good) and learn how to change the strings and tune the guitar.  EBay also has lots of great guitar strings for your new guitar.   Just think!   For under $200 you could be on your way, making great music and making new friends.   Good luck!