Er...

You don't require investors, you require customers.

I know many people running this type of business.

Startup cost is $0.

Well, whatever your site hosting costs every month.

Best starting point is just to research other Medical + Dental Tourism companies. Clone what they do.

Pay your time generating clients, not looking for investors... which you don't require... which will ask for a large chunk of your business... and likely won't talk with you, if you're just starting.

Intone this mantra all day long...

Customer not Investors...

Customer not Investors...

Customer not Investors...