The money tree pictured is one of mine (I have three because I think they're cool - I love the braided trunks and the structure of the leaves). It sits in the southeastern sector of my home and of my living room in an eastern-facing sunny window. I have another in a south facing sunny window and a third with southwestern exposure but away from the window. You'll notice I've also tied a red cord around the braided trunk. The cord has three feng shui prosperity coins tied with a mystic knot on it to further reinforce the theme of abundance.
Pachira aquatica are relatively easy to find and care for. I've seen them at floral shops, online, and even at Home Depot in the plant department. Look for a specimen with healthy olive green leaves and braided trunks without any obvious wounds to them. The trunks are braided when the plants are young and pliable so it doesn't harm them.
To care for your money tree, place it in well-drained soil in indirect indoor light. Too-bright direct sunlight can burn the leaves. Water it until water runs from the bottom holes once or twice a week when the soil starts to dry up. I tend to water mine every four to five days. Money trees also love humidity, so spritz it daily with water or place it with other plants grouped around a humidifier set on low. Make sure the plant never sits in standing water, which can cause root rot and kill the plant. Empty water from the water tray when it collects after watering. Transplant into a larger container every few years. This is easy to do because the root system of the tree is very close to the trunk, and it doesn't root deeply into soil. Fertilize three to four times each year, but don't overdo it.
That's it. These plants are wonderful and they can bring plenty of abundance juju to your home. They also help improve interior air quality, and they're lovely to look at. Mine have flourished in my home. Expect to pay about $30 to $50 for a good-sized tree or about $10 to $20 for a smaller plant.