For indoor work, such as in warehouses or stores, traditional gas forklifts are not going to be as cost-efficient and useful as an electric powered one. Electric forklifts are often designed to look and work similarly to gas ones, but they use electric batteries instead of gas. They're good for a couple of reasons. First, they save you money on fuel costs. They usually cost more initially, but they more than make up for it. When gas prices are higher, you save tons of money. They also tend to last much longer than gas forklifts. Second, for warehouses and other indoor applications, you avoid fumes. It can be very dangerous to use diesel forklifts or gas-based ones indoors.
There are some downsides, however. An electric forklift can usually only work for one 8 hour shift and then the battery needs to be charged for another shift. You can get around this with multiple batteries (you just rotate them out as the shift ends, then the other one is charged) but that will cost more. You also have to set up a battery changing station (which is actually pretty complicated, and will require some space).
You can get used electric forklifts online here: