The cost of running an inflatable hot tub depends on a few major factors: electricity, water, filters, cleaning and chemicals. To a lesser degree, other factors will contribute to hot tub maintenance costs, like its size, where you set it up, how often you use it and how strict you are about cleaning it. Electricity costs vary by state, so running a hot tub may be less expensive in Louisiana residents than in Alaska or Hawaii.
Portable spas used outside tend to lose heat quicker than those inside, while you would also use less power if you used it every day. The initial heating up of the water takes some time and pushed up your heating cost, whereas the more often you use it, the more the water temperature stays the same as you would only be increasing heat when the water cools down.
If you do like to move it around regularly, which is the strongest advantage for inflatable hot tubs, you have to deal with draining, deflating, moving, inflating, and refilling your tub every time you want to move it. The deflating and inflating isn’t as big of a deal if you have an air compressor to hook up to it, or if your hot tub came with its own, but it still takes a while (and a good deal of water) to refill that hot tub every time, and longer yet to get the water hot.