The last few years haven't been kind to gold investors.

After peaking in late 2011 near $1900 an ounce, gold has moved in one direction: down. Priced in U.S. dollars, the yellow metal has fallen more than 30% in the last three years.

Gold Price in US Dollars Chart

Gold Price in US Dollars data by YCharts

Investors looking to take advantage of a possible resurgence have many potential outlets. Below are three ways to invest in the precious metal.

1. Take delivery of bullion
Perhaps the most straightforward way to invest in gold is to simply purchase the metal outright. Gold bullion can be purchased online, through dealers or auction websites, in a variety of different weights. Gold Eagles, Krugerrands, and bars are freely available on eBay. They can also be purchased directly from a number of dealers including Apmex and Kitco.

Physical bullion has its advantages. You know what you own, and it's cheap to maintain. If you're so inclined, you can store it in a safe in your home, effectively eliminating holding costs, or rent out space at a depository.

2. Buy shares of a gold-backed ETF
But bullion also has its fair share of limitations. It's obviously not very liquid, and transaction costs can be significant. As I write this, the spot price of gold is $1,188, but a one ounce Krugerrand purchased on eBay goes for nearly $1,300 -- an almost 10% premium. That's just one example, and there may be less expensive ways to purchase it, but you'll rarely be paying the spot price.

If you want exposure to the price of gold, but don't want to take delivery, there are a few exchange-traded funds to consider. The largest and most commonly traded is the SPDR Gold Shares (NYSEMKT:GLD). iShares Gold Trust (NYSEMKT:IAU) is a smaller alternative.

Both GLD and IAU are backed by physical bullion stored in a warehouse. When you buy a share of either fund, you are buying an asset backed entirely by bullion. The price of both funds, then, trades quite closely with the spot price of the physical metal, allowing investors to "own gold" without the associated headaches that come with taking delivery of physical bullion.

It's important to note, however, that GLD shareholders don't actually own gold. Redemption is possible, but only for designated participants -- banks and broker-dealers. Still, if the price of gold is poised to surge, GLD and IAU should gain with it.

3. Invest in a company with gold exposure
Then there are ways to invest in gold without actually investing in gold. By that I mean gold miners -- companies whose financial performance depends almost entirely on the price of gold.

There are many large and diversified mining firms, but those looking to invest in gold in particular should seek out companies who derive almost all their revenue from gold mining. Goldcorp (NYSE:GG) is a prime example, and one of the best firms in its class.

Goldcorp's business depends on the spread between the price of gold and the cost to dig it out of the ground. Last quarter, it cost Goldcorp about $1,210 per ounce to mine gold (on an all-in sustaining cost basis). With gold trading at or even below that cost, the company isn't profitable, but if the price of gold were to head higher, it should return to profitability, and Goldcorp's shares could rebound.

Unfortunately, the business of mining is fraught with risk. Labor issues, government regulations, and political instability have taken a toll on mining stocks in the past. And because mining requires significant capital expenditures, low gold prices can easily put firms out of business.

Once purchased, gold bars may drop in value, but they'll never be worthless. The same can't be said for shares of a mining company. On the other hand, a successful firm can pay investors a steady stream of dividends -- gold bullion just sits there.