Gerbil supplies are available either at your local pet store or indeed online, if you buy the right supplies it shouldn't cost too much. In years gone by gerbils may be homed in cages or glass tanks, but nowadays the material of choice is acrylic, it's lightweight and secure. Once you have a suitable acrylic tank, you will need a secure lid with plenty of ventilation. It's particularly important to ensure either the lid clips into place or is held down with a suitable weight, this will not only prevent cats and the like getting in, but gerbils are known as good jumpers a good lid will ensure they stay inside the tank! Make sure the tank you buys comes with a suitable water drinking bottle, this should be accessible from the outside of the tank, meaning you can change or refill the gerbils water without need to enter the tank. Gerbils like to burrow, so your choice of tank lining is important. As gerbils produce very little urine, tank lining doesn't need to be changed very often, this means it's worth spending a little extra to buy a good quality lining, small animal bedding is widely available. Make sure you do not use sawdust as this can irritate the gerbils eyes. If you want to ensure your gerbils have plenty to do, you can bury some tubes into the lining, this will give them something to explore.
In addition to the base lining you should ensure there is additional loose bedding available as the gerbils will use this for lining their chambers, this is for nesting.
As a general rule changing the tank lining should take place once a week, you may have to do this slightly more often if you have a number of gerbils in the tank. You will need a suitable acrylic carrier to not only store the gerbil in whilst you clean the main tank, but also to serve as a carrier for any trips to the vet you may need. It's important to ensure this carrier is as secure as the main tank, this will avoid the gerbils escaping. Do not be tempted to buy a cheap cardboard carrier, gerbils tend to chew through these in minutes.
When it comes to buying in food, gerbils are pretty easy going, they like seeds, greenery and vegetables, they also enjoy invertebrates such as mealworms, just be sure to avoid oil based seeds as these can cause obesity. A small amount of hay makes a good fibrous addition to their diet. With such a simple diet your shouldn't need to look very far to find cheap supplies.