If you have $1,000 to invest and are looking for undervalued dividend stocks, you're in luck. The market has presented some attractive opportunities for income-oriented investors. Here are three dividend stocks that are currently on sale and offer compelling yields and growth prospects:

1. Pfizer (PFE)
* Current yield: 3.2%
* Forward P/E ratio: 7.9
* Dividend growth: 6-year CAGR of 6.5%
* Pfizer is a leading pharmaceutical company with a strong pipeline of new drugs and vaccines. The stock is undervalued based on its forward P/E ratio and offers a high dividend yield. The company has a history of dividend growth and is expected to continue raising its payout in the future.
2. Vale (VALE)
* Current yield: 9.0%
* Forward P/E ratio: 4.8
* Dividend growth: 5-year CAGR of 10.5%
* Vale is a global mining company with a focus on iron ore, copper, and nickel. The stock is undervalued based on its forward P/E ratio and offers an attractive dividend yield. Vale has a strong balance sheet and is expected to benefit from the global push towards green energy, which will increase demand for its products.
3. AT&T (T)
* Current yield: 5.9%
* Forward P/E ratio: 7.2
* Dividend growth: 5-year CAGR of 2.5%
* AT&T is a telecommunications giant that offers a mix of wireless, wireline, and satellite services. The stock is undervalued based on its forward P/E ratio and offers a high dividend yield. AT&T has a strong balance sheet and is expected to benefit from the continued growth of its wireless and fiber businesses.

These undervalued dividend stocks offer a combination of high yields, attractive valuations, and strong growth prospects. By investing in these companies, you can generate significant income and long-term capital appreciation. However, it's essential to conduct thorough research and consider your risk tolerance before making any investment decisions. Diversifying your portfolio across multiple sectors and asset classes can help mitigate risk and maximize returns.

In conclusion, if you have $1,000 to invest in undervalued dividend stocks, consider Pfizer, Vale, and AT&T. These companies offer attractive yields, strong growth prospects, and are currently trading at discounted valuations. By investing in these stocks, you can build a diversified income portfolio that will generate steady cash flows and long-term capital appreciation.