Not everyone would visit for the oil massage that would need lot of time. Some might want to enjoy the peaceful environment that exists inside of your spa. At the same time, it is advisable that you serve them some sort of automatic service that they would be interested in. Some people might be scary about the service that they get from people while some might be inconvenient. However, they may like the massage that wheel chairs could provide them. The normal chairs would not be able to do anything. So, it is advisable that you buy the electric wheelchairs from online store which is where you could evaluate lot many models and then pick the one the best fits your purpose.
You could check the capacity or the load that a chair could bear and thus you could buy some low end models and some chairs of high end models. Since you could be confident about getting returns on these chairs on a monthly basis, you could pay through your credit cards. Leverage the good credit score you have and also choose to take a loan if the limit of your credit card would not suffice for you to start this service on a large scale. Of course, people would be interested to leave their elderly parents at your spa or recreation center when you have such advanced equipment with you. Hence, the incoming customers would increase day by day. You could plan to make your service available online and thereby let the customers book the slots so that there is no waiting at your spa when the crowd suddenly increases.
Hope you would try this and make some money out of the simple but effective electric wheelchairs that are available online. Just follow the instructions to operate them and if some customers want to operate by self, then educate them with the steps.