What ever treatment you decide to offer you will need a portable/light weight massage couch. The most important first purchase you will make.
When I first started over 30 years ago that's what I had. I paid £230 for mine and it was not light weight , but it was sturdy. I know now there are many for around half that price....but it is up to you what your budget is.
like you I wasn't sure how busy I would become and I wanted the flexibility of both home and mobile with having a young family.
Massage :- costs just the price of almond oil or massage cream in terms of purchasing stock . It is just your time. The wear and tear on the body is tremendous so you wouldn't want to fit too many in one day as well as lugging a heavy couch too. Most of my clients only have the occasional back massage now to be honest because my hands, wrists and neck are quite arthritic. I try not to promote it anyway.
Hot stones :-cost just the hot stone kits and some massage medium. However factor in the additional time of heating up at the clients' house and the sterilisation afterwards and it's all a bit time consuming.
The stones are beautiful to receive , and there is no need for a full body massage which saves you time.
Facials :- as you have previously posted with regard to products the Kaeso range is perfectly priced for your new career, and you will need to add mask brush, sponges for removal, comedone extractor, and a bowl for hot water. collapsible trolley too.
I don't do make up anymore
Many wholesalers have starter kits which will give you an idea about what to buy, and they offer a little discount if bought as a package.
Search for second hand too, there also could be salons closing down sadly because of the massive disruption to normal life.