American Girl dolls are 18". Just do a google (or bing, or yahoo, or any of the search engines) search for 18" dolls and you will get loads of options. Walmart offers one for $20. Very bare bones with no accessories.
Just found this blog about all the 18" dolls out there but it is 5 years old and mentions Toys R Us which we know is no more. But this will give you an idea of all the options out there, expensive and inexpensive alike.
http://www.homegrownfamilies.net/201...-alternatives/