Phoenix-area homes sales in September jumped 17.7% from the year-ago period, spurred by an increase in home sales in the sub-$100,000 market, DataQuick said Friday. In September, the Phoenix area recorded 8,661 new and resale home and condo sales. Compared to August, sales fell 9.7%. But experiencing sales declines between August and September is normal, DataQuick said. The research firm’s market outlook covers home sales in Maricopa County, which includes Phoenix and is the fourth most populous county in the country, and Pinal County in the central part of Arizona. September sales in the below $150,000 price range jumped 22.8% over September 2010, while deals for homes under $100,000 increased 32.1% over last year. Sales in the $200,000-to-$600,000 range showed a gain of 9.8% over last year, while transactions valued over $500,000 fell 3.7%. In the over-$800,000 market, sales fell 4.6% year-over-year. Buyers paid a median home sales price of $124,500 in September, up 5.2% from August. The August median price is 52.9% above the peak sales level of $264,000 reached in June 2006. Activities driven by investors also declined last month. Foreclosure resales, cash-buying activity and lender repossessions also fell. Foreclosure homes and short sales, meanwhile, represented 61.2% of the Phoenix area resale market in September. Write to Kerri Panchuk.