A combination of low mortgage rates and prices kept real estate investors and first-time buyers hooked on the Las Vegas market in October, pushing existing home sales up 15.3% from last year, DataQuick said. The real estate analytics firm said buyer interest in homes valued below $100,000 jumped 33% over last year. Overall, 4,595 new and resale houses and condos closed in escrow last month. The total number of transactions below $100,000 climbed to 33.2% from a year ago, making up 41.3% of all deals compared to 34.8% of sales a year ago. Meanwhile, the number of sales below $200,000 last month rose 18.2% year-over-year, while the number of sales above $300,000 fell 4.4% from a year ago. October was the fourth consecutive month in which the Las Vegas market reported a year-over-year gain in total sales. DataQuick noted the year 2011 brought many buyers attracted to low cost homes into the market, putting the city on track to record the highest level of resale activity by year-end. Write to Kerri Panchuk.