I don’t about SD but I have 540 sq ft here in orange county for $1,100 a month on a year lease started at 900 a month two years ago. Craigslist is a good place to get an idea usually I post a listing with pictures and set price. Depending on the responses you can judge the demand for your rental. Last time I did a listing I got around 25 people a day calling and emailing with 5 people showing up a day and in a week had 5 solid renters (with good credit and good jobs)to choose from.