If you want low cost diversification to high quality stocks and bonds, then the list of exchange-traded funds (ETFs) below might be of great value to you. The catch is that we’re currently in unchartered investing waters, which has been fueled by 78 consecutive months of near zero interest rates. This, in turn, has led to debt fueled growth and too much corporate debt. At the same time, U.S. Federal debt is 101.5% of gross domestic product (GDP). On top of that, you have the retiring Baby Boomer generation, which drove consumer spending for decades. With all these Baby Boomers retiring, it will cost a lot for the government to take care of them. Put simply, entitlements will need to be cut. Additionally, in order to pay off massive government debts, it’s possible that taxes will need to be raised. However, even if that’s not the case, there are enough head winds for great concern.

While the four ETFs below are likely the best group of four you will find for long-term investing and diversification, this might not be the ideal time to jump in with two feet. That said since nobody truly knows how long the current bull run will last, you can jump in with one foot. This means only using a small percentage of your available capital to invest, thereby reducing risk without sacrificing upside potential. If the market continues to appreciate, then you still have a small win. If the market takes a hit, you have more capital available to buy at lower prices. It’s a win win as long as you’re patient. Now let’s get to those four high quality ETFs. (For more, see: Considering ETF Diversification.)

All numbers below as of May 22, 2015.

Vanguard Total Stock Market ETF

The Vanguard Total Stock Market ETF (VTI) tracks the performance of the CRSP Total Market Index. Translation: It tracks everything from micro caps to large caps. It also offers exposure to all sectors, making it broadly diversified. Currently, it has most exposure to technology (17.64% of net assets), healthcare (14.62%) and financial services (14.38%). VTI has an expense ratio of just 0.05% — the lowest you will find in the ETF universe. With over 2.5 million shares traded per day, there is also plenty of liquidity. A 1.81% dividend yield is a bonus. VTI has appreciated 11.48% over the past year. (For more, see: Vanguard Total Stock Market ETF.)

Vanguard Dividend Appreciation ETF

The Vanguard Dividend Appreciation ETF (VIG) tracks the performance of the U.S. Dividend Achievers Select Index. Translation: It tracks the performance of companies that have historically raised their dividend. Its largest holdings are Microsoft Corp. (MSFT), International Business Machines Corp. (IBM) and Johnson & Johnson. (JNJ), which represent 4.54%, 4%, and 3.96% of net assets, respectively. VIG has an expense ratio of 0.10%. This isn’t as low as VTI, but it’s still extraordinarily low considering the average expense ratio on an ETF is 0.46%. The dividend yield is 2.14%, and VIG has appreciated 7.13% over the past year. (For more, see: Minimizing ETF Fees.)

Vanguard FTSE Emerging Markets ETF

The Vanguard FTSE Emerging Markets ETF (VWO) tracks the FTSE Emerging Markets Index. It offers exposure to all sectors, with the most to financial services (27.07%) and technology (16.89%). VWO has an expense ratio of 0.15% (still very low). It’s currently yielding 2.52%, and has appreciated 86.36% over the past year.

Vanguard Total Bond Market ETF

The Vanguard Total Bond Market ETF (BND) offers exposure to U.S. investment-grade bonds. Over the long haul, this should be seen as a slow and steady investment. The bond holdings have an average effective maturity of 7.8 years and an average duration of 5.6 years. The expense ratio on BND is just 0.07%. The average expense ratio for similar funds is 0.85%. BND currently yields 2.46%. It has depreciated 0.24% over the past year. (For more, see: These Bond Funds Act Like Stocks.)

The Bottom Line

The ETFs listed above offer low costs, high liquidity, diversification and good long-term potential. That said, this might not be the best entry point. You may see much cheaper prices at some point over the next one to two years. (For more, see: Using ETFs to Build a Cost-Effective Portfolio.)

Dan Moskowitz does not have any positions in VTI, VIG, VWO or BND.