On average rental equipment
Reg set - $15 per day.
assuming 3 trips of total 15 days of diving will cost u $225 per year.
that includes you not knowing the condition of the equipment. If anyone vomited into it before etc. BUT it does reduce some weight on your luggage.
Oceanic do sells some good and light set.
BY good i means its usable and its really light compared to my mk25 S600.
It should cost less than 600.
you can look at divegearexpress for Hollis set probably cost ~600.
you can drop by Oceanic at parklane to check out Hollis, Alpha 9 or aeries.
Servicing reg is about $90-$180 every year.
this includes you making sure you do the job of bringing it down for servicing since your life depends on it.
no definite answer but you do the maths. lol.